Stefano Cicchi's Publications List

N-glycosylhydroxylamines as masked polyhydroxylated Chiral Nitrones in Cycloaddition Reactions : An Access to Pyrrolizidines

2009-09-08T16:17:03Z

Marco Marradi, Massimo Corsi, Stefano Cicchi, Marco Bonanni, Francesca Cardona, Andrea Goti (2009) Heterocycles 79: 883-896

Pyrene-Excimers-Based Antenna Systems

2009-09-08T16:17:03Z

A series of dendrimeric compounds bearing pyrene units were synthesized to afford light-harvesting antennae based on the formation of intramolecular excimers. The synthetic plan profited front the efficiency of the Huisgen reaction, the 1,3-dipolar cycloaddition of azides and terminal alkynes, which allowed ready assembly of the different building blocks. The three molecular antennae obtained, of ...

Stefano Cicchi, Pierangelo Fabbrizzi, Giacomo Ghini, Alberto Brandi, Paolo Foggi, Agnese Marcelli, Roberto Righini, Chiara Botta (2009) Chemistry-a European Journal 15: 3 754-764

Surface-enhanced fluorescence and surface-enhanced Raman scattering of ultrathin layers of bichromophoric antenna systems adsorbed on silver nanoisland films

2009-09-08T16:17:03Z

Emilia Giorgetti, Stefano Cicchi, Maurizio Muniz-Miranda, Giancarlo Margheri, Anna Giusti, Alessio Rindi, Giacomo Ghini, Stefano Sottini, Agnese Marcelli, Paolo Foggi Tommaso Del Rosso (2009) Journal of Luminescence ?:

Towards a general organogelator : combining a versatile scaffold and an efficient linking process

2009-09-08T16:17:03Z

A new organogelating moiety, 1, is proposed as a suitable and versatile building block for the production of other gelling compounds. Linking 1 with several different molecular fragments afforded new gels with different properties. A detailed investigation of the ferrocene substituted gelator is reported in this study.

Luisa Lascialfari, Claudia Vinattieri, Stefano Cicchi, Alberto Brandi, Debora Berti, Francesca Betti, Piero Baglioni Giacomo Ghini, Matteo Mannini (2009) Soft Matter http://www.rsc.org/Publishing/Journals/SM/article.asp?doi=b819345b# 5: 1863-1869

Five-membered ring systems with O & N atoms.

2009-09-08T16:20:06Z

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2009) 265-288

The triazine ring as a scaffold for the synthesis of new organogelators

2009-09-08T16:17:03Z

The synthesis of new organogelators based on a triazine nucleus is described together with the analysis of the properties of the main compound 15. This compound revealed an efficient organogelator in both polar and apolar solvents and represents a promising precursor of other functionalized organogelators. (c) 2008 Elsevier Ltd. All rights reserved.

Stefano Cicchi, Giacomo Ghim, Sara Fallani, Alberto Brandi, Debora Berti, Francesca Betti, Piero Baglioni (2008) Tetrahedron Letters 49: 10 1701-1705

Five-membered ring systems with O & N atoms.

2009-09-10T13:56:29Z

A review on five-membered ring systems with O and N atoms. This review covers recent progress in transition metal-catalyzed cross-coupling reactions using isoxazoles. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2008) 288-313

3-Spirocyclopropanedihydro- and -tetrahydropyridin-4-ones from nitrone cycloadducts of bicyclopropylidene via 1-(1 ‘-aminomethylcyclopropyl)-cyclopropanol under Pd-II catalysis

2009-09-08T16:17:03Z

A series of 3-spirocyclopropanedihydro- and -tetrahydropyrid-4-ones have been synthesized by nitrone cycloaddition to 1,1’-bicyclopropylidene (BCP), chemoselective reduction of the N-O bond of the isoxazolidine ring, and Pd-II-catalyzed cascade rearrangement of the beta-anunocyclopropanol derivatives into the final products. The new tetrahydropyridone derivatives were also prepared by thermal re...

Julia Revuelta, Stefano Cicchi, Armin de Meijere, Alberto Brandi (2008) European Journal of Organic Chemistry : 6 1085-109

Novel syntheses of azetidines and azetidinones

2009-09-08T16:17:03Z

Alberto Brandi, Stefano Cicchi, Franca M Cordero (2008) Chemical Reviews 108: 9 3988-4035

Formal mixed double addition to N-glycosylnitrones through addition-oxidation-addition to N-glycosylhydroxylamines

2009-09-08T16:17:03Z

A protocol for the formal mixed addition of two different C-nucleophiles at C1 and C1’of N-glycosylnitrones has been developed. Addition of Grignard reagents to N-erythrosyl-N-benzylhydroxylamine I affords hydroxylamines 6 almost quantitatively with high diastereoselectivity. These compounds undergo regioselective oxidation to the corresponding C-phenyl nitrones 7, which in turn add a second Gri...

Marco Bonanni, Marco Marradi, Stefano Cicchi, Andrea Goti (2008) Synlett : 2 197-202

Comprehensive Heterocyclic Chemistry III Bicyclic 5-6 Systems with One Bridgehead (Ring Junction) Nitrogen Atom: No Extra Heteroatom 0:0

2009-09-10T13:59:33Z

Stefano Cicchi Alberto Brandi (2008)

The ultrafast energy transfer process in naphtole-nitrobenzofurazan bichromophoric molecular systems - A study by ferntosecond UV-vis pump-probe spectroscopy

2009-09-08T16:17:03Z

This work presents an experimental and computational study of the intramolecular electronic energy transfer process occurring in two newly synthesized bichromophoric species: N-(7-nitro-2,1,3-benzoxadiazol-4-yl)amino-bis-ethyl-2-[(4-chloro-1-nap hthyl)oxy]acetate (f-Bi) and N-(7-nitrobenzo[c][1,2,5]oxadiazole-4-yl)-(3S, 4S)-pyrrolidin-3,4-bis-yl-2-[(4-chloro-1-naphthyl)oxy]acetate (r-Bi). In both ...

Pier Luigi Gentili, Martina Mugnai, Laura Bussotti, Roberto Righini, Paolo Foggi, Stefano Cicchi, Giacomo Ghini, Simone Viviani, Alberto Brandi (2007) Journal of Photochemistry and Photobiology A-Chemistry 187: 2-3 209-221

(3S, 4S)-1-Benzyl-4-(N-octylcarbamoyloxy) pyrrolidin-3-yl N-octylcarbamate : a low-temperature redetermination

2009-09-08T16:17:03Z

The title compound, C29H49N3O4, is a model compound synthesized to obtain information on the intermomecular forces that drive the self-assembly of a similar compound bearing longer aliphatic chains. In the crystal, molecules are arranged in columns due to the formation of two antiparallel strong hydrogen-bonded chains by the carbamate units. The two long aliphatic chains are trans.

Stefano Cicchi, Cristina Faggi, Giacomo Ghini, Annalisa Guerri, Jacopo Parlanti (2007) Acta Crystallographica Section E-Structure Reports Online 63: Part 7

Five-membered ring systems with O & N atoms.

2009-09-10T13:57:16Z

A review. The prepn. and reactions of five-membered nitrogen-oxygen heteorcyclic compds. are reviewed. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2007) 288-309

Synthesis of densely functionalized enantiopure indolizidines by ring-closing metathesis (RCM) of hydroxylamines from carbohydrate-derived nitrones

2009-09-08T16:17:03Z

Background: Indolizidine alkaloids widely occur in nature and display interesting biological activity. This is the reason for which their total synthesis as well as the synthesis of non-natural analogues still attracts the attention of many research groups. To establish new straightforward accesses to these molecules is therefore highly desirable. Results: The ring closing metathesis (RCM) of enan...

Marco Bonanni, Marco Marradi, Francesca Cardona, Stefano Cicchi, Andrea Goti (2007) Beilstein Journal of Organic Chemistry 3:

A new organogelator based on an enantiopure C-2 symmetric pyrrolidine

2009-09-08T16:17:03Z

The synthesis and the properties of a new chiral organogelator based on a C-2 symmetric pyrrolidine, are described together with its use for the synthesis of other functionalised organogelators.

Stefano Cicchi, Giacomo Ghini, Luisa Lascialfari, Alberto Brandi, Francesca Betti, Debora Berti, Silvia Ferrati, Piero Baglioni (2007) Chemical Communications : 14 1424-1426

Enantiopure cyclic nitrones : A useful class of building blocks for asymmetric syntheses

2009-09-08T16:17:03Z

The synthesis of enantiopure cyclic nitrones has become a frequently addressed topic in discussions of their usefulness in the production of natural products and biologically active compounds. This emphasis has stimulated the development of a variety of synthetic approaches that are described in this review, organized on the basis of the size of the nitrone ring.

Julia Revuelta, Stefano Cicchi, Andrea Goti, Alberto Brandi (2007) Synthesis-Stuttgart : 4 485-504

Synthesis of enantiopure indolizinones by cascade ring enlargements of 4 ‘-chlorospiro[cyclopropane-1,5 ‘-isoxazolidines]

2009-09-08T16:17:03Z

2-Chloro-2-cyclopropylideneacetates (1-Me and 1-Et) and their spiropentane analogues 2 cycloadd enantiopure five-membered cyclic nitrones to give the corresponding adducts (quantitatively, four examples), which undergo cascade ring enlargements to yield indolizinone derivatives (53-70%, four examples). The ring enlargement process is triggered by the abstraction of a bridgehead proton induced by a...

J Revuelta, S Cicchi, C Faggi, S I Kozhushkov, A N de Meijere, A Brandi (2006) Journal of Organic Chemistry 71: 6 2417-2423

One-pot synthesis of cyclic nitrones and their conversion to pyrrolizidines : 7a-epi-crotanecine inhibits alpha-mannosidases

2009-09-08T16:17:03Z

A new straightforward and inexpensive one-pot procedure is described for the preparation of enantiopure five-membered cyclic nitrones starting from the corresponding lactols. Its efficiency relies on the condensation of unprotected hydroxylamine with readily available lactols and on the chemoselectivity of the subsequent esterification with methanesulfonyl chloride. The targeted enantiomerically p...

S Cicchi, M Marradi, P Vogel, A Goti (2006) Journal of Organic Chemistry 71: 4 1614-1619

Double addition of grignard reagents to N-glycosyl nitrones : A new tool for the contruction of enantiopure azaheterocycles

2009-09-08T16:17:03Z

C-Pheynl-N-erythrosylnitrone 3 behaves as a C1,C1’ bis-electrophile, undergoing a double addition of Grignard reagents in a domino fashion to afford acyclic hydroxylamines 4. The reaction proceeds at 0 degreesC with variable degrees of diastereoselectivity, from moderate to good. mainly depending on the organomagnesium reagent used. The usefulness of compounds 4 has been exemplified with the syn...

M Bonanni, M Marradi, S Cicchi, C Faggi, A Goti (2005) Organic Letters 7: 2 319-322

Straightforward synthesis of enantiopure 2-aminomethyl and 2-hydroxymethyl pyrrolidines with complete stereocontrol

2009-09-08T16:17:03Z

A practical synthesis of 2-aminomethyl- and 2-hydroxymethyl-3,4-dihydroxypyrrolidines via stereocontrolled addition of TMSCN and LiCH2OMOM to chiral 3,4 dihydro-2H-pyrroline N-oxides is reported. (C) 2004 Elsevier Ltd. All rights reserved.

M Marradi, S Cicchi, J I Delso, L Rosi, T Tejero, P Merino, A Goti (2005) Tetrahedron Letters 46: 8 1287-1290

Imidic acids and derivatives. C-heteroatom-substituted nitrones, other dipoles.

2009-09-10T14:03:43Z

A review of the prepn. and synthetic applications of of imidic acid derivs. featuring C-heteroatom-substituted nitrones and other dipoles. [on SciFinder(R)]

F M Cordero, S Cicchi (2005) Science of Synthesis 267-330

Imidic acids and derivatives. Carbon-substituted iminium salts.

2009-09-10T14:03:13Z

A review of the prepn. and synthetic applications of carbon-substituted iminium salts. [on SciFinder(R)]

S Cicchi, F M Cordero (2005) Science of Synthesis 221-266

Two-step metal-mediated transformation of isoxazolidine-5-spirocyclopropanes into pyridone derivatives

2009-09-08T16:17:03Z

The two-step metal-catalyzed overall transformation of isoxazolidine-5-spirocyclopropanes into the corresponding dihydro- and tetrahydropyridones is described. The first step is the chemoselective reduction of the N-O bond of the isoxazolidine ring preserving the fragile cyclopropanol moiety while the second transformation is the Pd(II) or Pd(O) conversion of the beta-aminocyclopropanol derivative...

J Revuelta, S Cicchi, A Brandi (2005) Journal of Organic Chemistry 70: 14 5636-5642

Samarium(II) iodide reduction of isoxazolidines

2009-09-08T16:17:03Z

SmI2 was used as reducing agent for the N-O bond cleavage in isoxazolidines. The procedure revealed is general and particularly useful for the transformation of 5-spirocyclopropane isoxazolidines to the corresponding beta-aminocyclopropanols, a troublesome transformation with other known reagents. (C) 2004 Elsevier Ltd. All rights reserved.

J Revuelta, S Cicchi, A Brandi (2004) Tetrahedron Letters 45: 45 8375-8377

Fully stereoselective nucleophilic addition to a novel chiral pyrroline N-oxide : total syntheses of (2S,3R)-3-hydroxy-3-methylproline and its (2R)-epimer.

2009-09-08T16:17:03Z

A new total synthesis of (2S,3R)-3-hydroxy-3-methylproline has been performed via a key intermediate chiral pyrroline N-oxide, obtained from (R)-citramalic acid. This nitrone underwent nucleophilic addn. of furyllithium with complete stereoselectivity through a preferential attack anti to the methoxymethoxy group. The correct stereochem. was established through an oxidn.-redn. sequence, which allo...

Pedro Merino, Julia Revuelta, Tomas Tejero, Stefano Cicchi, Andrea. Goti (2004) Eur. J. Org. Chem. : 776-782

Five-membered ring systems with O & N atoms.

2009-09-10T13:59:58Z

A review covering the syntheses and reactivity of oxazole and isoxazole and their derivs. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2004) 283-308

Critical surveys covering the year 2003. Total synthesis of natural products.

2009-09-10T14:00:42Z

A review on total syntheses of natural products published in the most important journals of org. chem. (listed) during the year 2003 (partial and formal syntheses as well as syntheses of structural analogs are excluded; also syntheses of nucleotides, nucleic acids, polypeptides, and polysaccharides are not referred). The total syntheses of (-)-tetrodotoxin and (+)-discodermolide are discussed in d...

Francesca Cardona, Stefano. Cicchi (2004) 331-363

Stereoselective synthesis of new bicyclic N,O-iso-homonucleoside analogues

2009-09-08T16:17:03Z

The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homonucleoside and are synthesised through a 1,3-dipolar cycloaddition of an enantiopure cyclic nitrone to protected allyl acohol and subsequent introduction of thymine by a Mitsunobu reaction. (C) 2003 Elsevier Science Ltd. All rights reserved.

B Richichi, S Cicchi, U Chiacchio, G Romeo, A Brandi (2003) Tetrahedron 59: 28 5231-5240

Preparation of N-glycosylhydroxylamines and their oxidation to nitrones for the enantioselective synthesis of isoxazolidines

2009-09-08T16:17:03Z

N-benzyl- and N-methyl-N-glycosylhydroxylamines 3a-i were conveniently obtained by reaction of sugars with N-substituted hydroxylamines according to a novel procedure. Subsequent oxidation occurred at the alkyl group, selectively affording the corresponding C-phenyl- and C-unsubstituted N-glycosylnitrones. C-phenyl-N-glycosylnitrones 10 and 13 under-went highly stereoselective 1,3-dipolar cycloadd...

S Cicchi, M Marradi, M Corsi, C Faggi, A Goti (2003) European Journal of Organic Chemistry : 21 4152-4160

Synthesis of new enantiopure bicyclic 1,2-oxazines by addition of lithiated methoxyallene to chiral cyclic nitrones

2009-09-08T16:17:03Z

A highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N-hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2-oxazines 6 and 7 by simple stirring in dilute CH22Cl solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2-oxazine 6 and amine oxide 8. Hydroboration of 7 furnished the h...

R Pulz, S Cicchi, A Brandi, H U Reissig (2003) European Journal of Organic Chemistry : 7 1153-1156

A comparative study of the stereoselective addition of trimethylsilyl cyanide and diethylaluminum cyanide to chiral cyclic nitrones

2009-09-08T16:17:03Z

The mild cyanating agent trimethylsilyl cyanide adds with total stereo selectivity to alpha-alkoxy cyclic nitrones to afford the corresponding trans-hydroxyaminonitriles. The addition of Lewis acids to precomplexing the nitrones does not affect the stereoselectivity of these additions significantly. In all of the cases examined, excellent yields of diastereomerically homogeneous products were obta...

P Merino, T Tejero, J Revuelta, P Romero, S Cicchi, V Mannucci, A Brandi, A Goti (2003) Tetrahedron - Asymmetry 14: 3 367-379

Five-membered ring systems : with O & N atoms.

2009-09-10T14:01:25Z

A review on the current advances in the chem. of five-membered ring systems with O and N atoms, particularly isoxazoles, isoxazolines, isoxazolidines, oxazoles, oxazolines, oxazolidines, and oxadiazoles. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2003) 261-283

Heterocycles from alkylidenecyclopropanes

2009-09-08T16:17:03Z

A Brandi, S Cicchi, F M Cordero, A Goti (2003) Chemical Reviews 103: 4 1213-1269

Iterative organometallic addition to chiral hydroxylated cyclic nitrones : Highly stereoselective syntheses of alpha,alpha ‘- and alpha,alpha-substituted hydroxypyrrolidines

2009-09-08T16:17:03Z

Iteration of organometallic addition to chiral hydroxylated pyrroline N-oxides through an addition-oxidation-addition synthetic sequence allowed highly stereoselective double alkylation of pyrrolidine at C-2 or at C-2 and C-5 depending on the regioselectivity of the oxidation step. Application of this methodology has been exemplified by the synthesis of the all-substituted pyrrolidine alkaloid (-)...

A Goti, S Cicchi, V Mannucci, F Cardona, F Guarna, P Merino, T Tejero (2003) Organic Letters 5: 22 4235-4238

Indium-mediated reduction of hydroxylamines to amines

2009-09-08T16:17:03Z

[GRAPHICS] A novel and simple procedure for reduction of hyproxylamines to the corresponding amines by means of indium powder in aqueous media is reported. Applicability to one-pot reactions and isoxazolidine N-O bond reduction is also demonstrated. A catalytic version of the process using 2-5% In in the presence of other metals (Zn, Al) has been successfully developed.

S Cicchi, M Bonanni, F Cardona, J Revuelta, A Goti (2003) Organic Letters 5: 10 1773-1776

A new 3,4-dihydroxypyrrolidine-based material for molecular recognition

2009-09-08T16:17:03Z

The synthesis of a new pseudopeptide material based on a chiral pyrrolidine skeleton is described. One of these new compounds interacts, in chloroform solution, selectively with amines.

S Cicchi, V Paschetta, A Brandi (2003) Arkivoc : Part 14 98-106

Domino palladium(II)-mediated rearrangement-oxidative cyclization of beta-aminocyclopropanols

2009-09-08T16:17:03Z

beta-Aminocyclopropanols were transformed, in a domino process catalyzed by Pd(II) salts, into the corresponding 2,3-dihydro-1H-pyridin-4-ones. Conversely the use of a Pd(0) derivative, Pd(dba)(2), afforded the corresponding tetrahydropyrid-4-ones. The saturated derivatives were also obtained, in better yields, using Pd(II) and Cu(OAc)(2) as stoichiometric oxidant.

S Cicchi, J Revuelta, A Zanobini, M Betti, A Brandi (2003) Synlett : 15 2305-2308

Chemo-, regio- and stereoselective Mitsunobu reaction of unprotected pyrimidine bases with hydroxypyrrolidines

2009-09-08T16:17:03Z

Unprotected pyrimidine bases were used in Mitsunobu reaction to afford in high yield new substituted pyrrolidines. The reaction is chemo-, regio- and stereoselective affording exclusively N-1 alkylated derivatives of (3S)-N-benzyl-3-hydroxy-pyrrolidine and (3S,4S)-N-benzyl-3,4-dihydroxypyrrolidine. (C) 2002 Elsevier Science Ltd. All rights reserved.

B Richichi, S Cicchi, U Chiacchio, G Romeo, A Brandi (2002) Tetrahedron Letters 43: 22 4013-4015

Straightforward synthesis of enantiomerically pure (3S,4R)- and (3R,4S)-3,4-isopropylidenedioxypyrroline 1-oxide, precursors of functionalized cis-dihydroxy azaheterocycles, by a novel “one-pot” procedure

2009-09-08T16:17:03Z

The enantiomerically pure nitrone 3, a valuable precursor of mono- and bicyclic azaheterocycles, has been synthesized in 57% yield by a novel “one-pot” process starting from lactol 1, in turn readily available from D-arabinose. The same process, consisting of reaction with a O-silyl-protected hydroxylamine followed by mesylation in pyridine. furnished ent-3 in 55% yield when applied to L-arabi...

S Cicchi, M Corsi, A Brandi, A Goti (2002) Journal of Organic Chemistry 67: 5 1678-1681

Five-membered ring systems : with O and N atoms.

2009-09-10T14:01:50Z

A review discusses the reaction mechanism, synthesis, structure and properties of various oxygen and nitrogen heteroatoms, such as isoxazoles, isoxazolines, isoxazolidines, oxazoles, oxazolines oxazolidines, and oxadiazoles. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2002) 235-256

Synthesis of new Fmoc-protected iminosugars to study the role of the glycosyl moiety in autoantibody recognition in autoimmune diseases.

2009-09-08T16:17:03Z

The authors were able to observe that the conjugation of a glycosyl moiety to an Asn (N-glycosidic linkage) in the glycopeptide CSF114(Glc) allowed the detection of specific antibodies in sera of patients with multiple sclerosis (MS). Data showed the relevance of the presence of a sugar moiety, favorably presented by a Î²-hairpin structure to a glycosylated epitope, for antibody recognition in M...

Francesca Nuti, Stefano Cicchi, Elisa Peroni, Maria de la Cruz Pozo-Carrero, Benedetta Mazzanti, Marta Pazzagli, Francesco Lolli, Mario Chelli, Anna Maria Papini, Alberto. Brandi (2002) Pept. 2002, Proc. Eur. Pept. Symp., 27th : 238-239

A new nitrone from C-2 symmetric piperidine for the synthesis of hydroxylated indolizidinone

2009-09-08T16:17:03Z

The oxidation of a C-2 symmetric piperidine, obtained through a ring enlargement process of the enantiopure protected (4R)-hydroxy-(2S)-hydroxymethyl pyrrolidine, is reported. Oxidation with C-phenyl-N-phenylsulfonyloxaziridine afforded the corresponding nitrone that is too unstable for isolation and which reacted in situ with dimethyl maleate. The major adduct was transformed to the corresponding...

A Brandi, S Cicchi, V Paschetta, D G Pardo, J Cossy (2002) Tetrahedron Letters 43: 51 9357-9359

Practical synthesis of N-alkyl-N-glycosylhydroxylamines, multitalented precursors of enantiomerically pure nitrones

2009-09-08T16:17:03Z

A practical synthesis of N-benzyl-N-glycosylhydroxylamines 3 (R = CH2Ph) is reported. The ability of these compounds to act as versatile synthetic intermediates is demonstrated by their oxidation followed by cycloaddition to N-glcosyl isoxazolidines and by the novel direct cycloaddition as masked acyclic. highly functionalized chiral nitrones. (C) 2002 Elsevier Science Ltd. All rights reserved.

S Cicchi, M Corsi, M Marradi, A Goti (2002) Tetrahedron Letters 43: 15 2741-2743

Cyclopentene anellation on assorted heterocyclic skeletons by vinylcyclopropane rearrangement

2009-09-08T16:17:03Z

Several alpha -spirocyclopropanated heterocyclic ketones were converted to the corresponding cyclopentene-anellated heterocycles in moderate to good yields (overall 31-60%) by Wadsworth-Emmons olefination followed by thermal rearrangement of the formed vinylcyclopropanes. In this sequence, the phosphonoacetonitrile was found to be superior to phosphonoacetate in the Wadsworth-Emmons olefinations o...

A Brandi, S Cicchi, M Brandl, S I Kozhushkov, A de Meijere (2001) Synlett : 3 433-435

Five-membered ring systems : With O & N atoms.

2009-09-10T14:02:10Z

A review on the synthesis of five-membered heterocycles contg. oxygen or nitrogen atoms. Examples of compds. prepd. include isoxazoles, isoxazolines, isoxazolidines, oxazoles, oxazolines, oxazolidines, and oxadiazoles. [on SciFinder(R)]

Stefano Cicchi, Franca M Cordero, Donatella. Giomi (2001) 217-237

Cyclobutylidenecyclopropane : New synthesis and use in 1,3-dipolar cycloadditions - A direct route to spirocyclopropane-annulated azepinone derivatives

2009-09-08T16:17:03Z

Cyclobutylidenecyclopropane (7) was prepared in multigram quantities by a new three-step sequence starting from ethyl cyclobutanecarboxylate (4) (39% overall yield), 1,3-Dipolar cycloadditions of phenyl- (9), pyridyl- (10), and the newly prepared (four steps, 43% overall yield) spirocyclic nitrone 11 onto 7 resulted in the regioselective formation of the corresponding adducts 15-17, with the spiro...

A de Meijere, M von Seebach, S I Kozhushkov, R Boese, D Blaser, S Cicchi, T Dimoulas, A Brandi (2001) European Journal of Organic Chemistry : 20 3789-3795

Manganese dioxide oxidation of hydroxylamines to nitrones

2009-09-08T16:17:03Z

Several structurally differentiated N,N-dialkylhydroxylamines were oxidised to the corresponding nitrones using MnO2. Manganese dioxide revealed an efficient and mild reagent for oxidation of hydroxylamines, showing a level of regioselectivity comparable to HgO. Its non-toxicity makes MnO2 the reagent of choice for replacing HgO in this oxidation. (C) 2001 Elsevier Science Ltd. All rights reserved...

S Cicchi, M Marradi, A Goti, A Brandi (2001) Tetrahedron Letters 42: 37 6503-6505

Synthesis of enantiopure protected 3-hydroxy-4-amino pyrroline N-oxides

2009-09-08T16:17:03Z

The synthesis of new five-membered enantiopure cyclic nitrones bearing protected cis vicinal amino and hydroxy functionalities is reported. The key step was a Mitsunobu reaction, which allowed placement of an azido group, with inversion of configuration, at the reacting centre. Cycloaddition of the novel nitrones to but-3-en-1-ol followed by simple elaboration of the adducts readily afforded prote...

S Cicchi, P Ponzuoli, A Goti, A Brandi (2000) Tetrahedron Letters 41: 10 1583-1587

Imino-sugars by stereoselective processes employing pyrroline N-oxides.

2009-09-08T16:17:03Z

The total synthesis of natural products requires selective methods to adapt to the structural complexity the nature has introduced in natural compds. From this challenge derives the impetus to find new reactions, new reagents and new catalysts to run reactions in a chemoselective, regioselective and stereoselective way. Recently, domino or multicomponent, combinatorial or enzymic processes, have e...

Alberto Brandi, Stefano Cicchi, Franca M Cordero, Andrea. Goti (2000) Proc. ECSOC-3, Proc. ECSOC-4, 1999, 2000 : 922-932

Enantiopure pyrroline-N-oxides in the synthesis of hydroxylated pyrrolizidine and indolizidine alkaloids.

2009-09-08T16:17:03Z

A Brandi, S Cicchi, F M Cordero, A Goti (2000) Abstracts of Papers of the American Chemical Society 219: Part 2

Straightforward access to enantiomerically pure, highly functionalized pyrrolizidines by cycloaddition of maleic acid esters to pyrroline N-oxides derived from tartaric, malic and aspartic acids - Synthesis of (-)-hastanecine, 7-epi-croalbinecine and (-)-croalbinecine

2009-09-08T16:17:03Z

The cycloaddition reactions of dimethyl maleate to three functionalized enantiopure pyrroline N-oxides and one related racemic nitrone are reported. The study of the diastereoselectivity in the cycloaddition has been carried out by ample variation of the substituents at both the dipole and dipolarophile counterparts. The major cycloadducts, derived from the preferred exo-anti transition states and...

A Goti, S Cicchi, M Cacciarini, F Cardona, V Fedi, A Brandi (2000) European Journal of Organic Chemistry : 21 3633-3645

Dendrimers : synthesis methods and recent application developments.

2009-09-08T16:17:03Z

A review with 39 refs., on synthetic methods, properties, and applications of dendrimers and dendritic polymers. Synthetic methods (convergent and divergent routes), catalysts, and selection of core species are discussed. Characteristics of metallo-dendrimers, supramol. structure, and applications of dendrimers in catalysis, encapsulation, and mol. recognition are described. [on SciFinder(R)]

Stefano. Cicchi (2000) Chim. Ind. (Milan) 82: 433-440

A straightforward route to enantiopure pyrrolizidines and indolizidines by cycloaddition to pyrroline N-oxides derived from the chiral pool

2009-09-08T16:17:03Z

Enantiomerically pure, five membered cyclic nitrones, easily obtained in large amounts from protected hydroxyacids and aminoacids such as D- and L-tartaric, L-malic, and L-aspartic acids, give cycloaddition reactions with a good diastereocontrol. The adducts of L-malic and L-aspartic acids derived from addition of nitrones to dimethyl maleate and gamma-crotonolactone were easily converted into ena...

A Goti, S Cicchi, F M Cordero, V Fedi, A Brandi (1999) Molecules 4: 1 1-12

Enantiopure pyrroline-N-oxides for the synthesis of pyrrolizine and indolizine alkaloids.

2009-09-08T16:17:03Z

A review with 17 refs. in which hydroxylated pyrroline-N-oxides provide a general entry to the synthesis of polhydroxylated pyrrolizidine and indolizidine alkaloids. [on SciFinder(R)]

Alberto Brandi, Francesca Cardona, Stefano Cicchi, Franca M Cordero, Andrea. Goti (1999) Curr. Trends Org. Synth., [Proc. Int. Conf. ], 12th : 213-220

Asymmetric and doubly asymmetric 1,3-dipolar cycloadditions in the synthesis of enantiopure organophosphorus compounds.

2009-09-08T16:17:03Z

The symposium proceedings from 14th conference on phosphorus chem. is reviewed with 12 refs. Enantiopure five-membered ring nitrones derived from L-tartaric acid and from L-malic acid undergo highly regio- and stereoselective cycloaddn. reactions with an excess of racemic 2,3-dihydro-1-phenyl-1H-phospholes producing two readily separable tricyclic cycloadducts and concomitantly effecting kinetic r...

K Michal Pietrusiewicz, Wieslawa Holody, Marek Koprowski, Stefano Cicchi, Andrea Goti, Alberto. Brandi (1999) Phosphorus, Sulfur Silicon Relat. Elem. 144-146: 389-392

Inexpensive and environmentally friendly oxidation of hydroxylamines to nitrones with bleach

2009-09-08T16:17:03Z

S Cicchi, M Corsi, A Goti (1999) Journal of Organic Chemistry 64: 19 7243-7245

Oxidation of hydroxylamines to nitrones catalyzed by (salen)Mn(III) complexes. Enantioselective synthesis of a protected cis-dihydroxypyrroline N-oxide with Jacobsen catalyst

2009-09-08T16:17:03Z

Oxidation of N,N-disubstituted hydroxylamines to nitrones catalyzed by the Jacobsen catalyst occurs cleanly in the presence of hydrogen peroxide, sodium hypochlorite or iodosylbenzene as the stoichiometric oxidant. Meso 3,4-cis-isopropylidenedioxy-1-hydroxypyrrolidine gave the corresponding protected 3,4-cis-dihydroxypyrroline N-oxide in an enantioenriched fashion for the first time (up to 36% e.e...

S Cicchi, F Cardona, A Brandi, M Corsi, A Goti (1999) Tetrahedron Letters 40: 10 1989-1992

New enantiomerically pure oligomeric macrocycles based on a 3,4-dihydroxypyrrolidine nucleus

2009-09-08T16:17:03Z

(3S,4S)-N-Benzyl-3,4-dihydroxypyrrolidine 1 has been used as a building block for new enantiopure macrocyclic polyesters, Two different synthetic approaches are presented leading to complementary results, The structure of the macrocycles synthesized has been confirmed by NMR spectroscopy and FAB mass spectrometry, and that for dimer 8 has been confirmed by X-ray analysis.

S Cicchi, E Chierroni, A Goti, A Brandi, A Guerri, P Orioli (1998) Journal of The Chemical Society-Perkin Transactions 1 : 2 367-370

Enantiomerically pure dendrimers based on a trans-3,4-dihydroxypyrrolidine

2009-09-08T16:17:03Z

The synthesis of the first and second generation of enantiopure dendrimers based on a chiral trans-3,4-dihydroxypyrrolidine is reported. Benzenepolycarboxylic acids were used as central nucleus to afford linear and radial growth, and terephthalic acid was used as spacer between the pyrrolidine nuclei. The analysis of the chiroptical properties ([alpha](D), circular dichroism) of these new dendrime...

S Cicchi, A Goti, C Rosini, A B Brandi (1998) European Journal of Organic Chemistry : 11 2591-2597

Domino processes involving pericyclic reactions.

2009-09-10T14:05:15Z

Review with 149 refs. [on SciFinder(R)]

Alberto Brandi, S Cicchi (1998) 33-60

Formal desymmetrization by a “Mitsunobu trick” - Enantiomerically pure cis-3,4-dihydroxypyrroline N-oxides for the enantiodivergent synthesis of trihydroxyindolizidines

2009-09-08T16:17:03Z

A protocol is presented for a completely enantioselective format desymmetrization of C-s-symmetric diols by monoprotection of the corresponding enantiopure C-2 diols, followed by an inversion of configuration by a Mitsunobu reaction (”Mitsunobu trick”). Its application to the unprecedented synthesis of enantiopure cis-3,4-dihydroxypyrroline N-oxides, employed in the enantiodivergent synthesis ...

S Cicchi, J Nunes, A Goti, A Brandi (1998) European Journal of Organic Chemistry : 3 419-421

Synthesis of enantiopure 3-substituted pyrroline N-oxides by highly regioselective oxidation of the parent hydroxylamines : A mechanistic rationale

2009-09-08T16:17:03Z

The syntheses of four new, differently O-substituted 3-hydroxypyrroline N-oxides and the first 3-amino analogue have been performed by the use of a strategy involving double nucleophilic displacement of the corresponding dimesylates by hydroxylamine and oxidation of the resulting 1-hydroxypyrrolidines. The regioselectivity data of the oxidation reactions nicely confirm the mechanistic hypothesis, ...

A Goti, S Cicchi, V Fedi, L Nannelli, A Brandi (1997) Journal of Organic Chemistry 62: 10 3119-3125

Synthesis of new enantiopure gamma-aminoalcohols : Their use as catalysts in the alkylation of benzaldehyde by diethylzinc

2009-09-08T16:17:03Z

The straightforward synthesis of new enantiopure gamma-aminoalcohols through 1,3-dipolar cycloadditon to a chiral cyclic nitrone derived from L-malic acid is described. Results of the application of these compounds as chiral catalysts in the alkylation of benzaldehyde with diethylzinc are also reported. (C) 1997 Elsevier Science Ltd.

S Cicchi, S Crea, A Goti, A Brandi (1997) Tetrahedron - Asymmetry 8: 2 293-301

Synthesis and X-ray study of hexahydro- and tetrahydrophospholo[2,3-d]isoxazoles, a new class of heterocycles of potential fungicidal activity

2009-09-08T16:17:03Z

Hexahydro-, 5b-1 and 6a,f,l and tetrahydropho spholo[2,3-d]isoxazoles 8, 9 and 10 were synthesized by 1,3-dipolar cycloaddition of nitrones 3b-1 and benzonitrile oxide (4) to 2,3-dihydro-1-phenyl-1H-phosphole 1-oxide (1) and 2,3-dihydro-1-ethoxy-1H-phosphole 1-oxide (2). The structural assignment to the compounds was confirmed by an X-ray study of two compounds of the series 5a and 5m. The compoun...

F Machetti, B Anichini, S Cicchi, A Brandi, W Wieczorek, K M Pietrusiewicz, J C Gehret (1996) JOURNAL OF HETEROCYCLIC CHEMISTRY 33: 4 1091-1098

The 2,2’-coupled pyrrolidine-phospholane ring system : A highly enantioselective synthesis and kinetic resolution of the phosphorus centre.

2009-09-08T16:17:03Z

A Brandi, S Cicchi, A Goti, M Koprowski, K M Pietrusiewicz (1996) PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 111: 1-4

Direct chromatographic resolution of P-chiral organophosphorus compounds at analytical and preparative levels.

2009-09-08T16:17:03Z

F Gasparrini, F Maggio, C Villani, A Brandi, S Cicchi, K M Pietrusiewicz, M Koprowski (1996) PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 111: 1-4

Assignment of the Absolute Configuration of Natural Lentiginosine by Synthesis and Enzymic Assays of Optically Pure (+) and (-)-Enantiomers.

2009-09-08T16:17:03Z

The structure and abs. configuration of natural (+)-lentiginosine (I) isolated from plant sources was detd. to be (1S,2S,8aS)-1,2-dihydroxyindolizidine on the basis of synthesis of both enantiomers and their inhibition of amyloglucosidases. (+)-I was derived from (L)-(+)-tartaric acid via a highly stereo- and regioselective 1,3-dipolar cycloaddn. of (3S,4S)-3,4-bis[(tert-butyldiphenylsilyl)oxy]-1-...

Alberto Brandi, Stefano Cicchi, Franca M Cordero, Roberta Frignoli, Andrea Goti, Sylviane Picasso, Pierre. Vogel (1995) J. Org. Chem. 60: 6806-12

DIRECT CHROMATOGRAPHIC RESOLUTION OF P-CHIRAL PHOSPHINOYLETHENES ON A CHIRAL STATIONARY-PHASE CONTAINING N,N’-(3,5-DINITROBENZOYL)-TRANS-1,2-DIAMINOCYCLOHEXANE AS SELECTOR

2009-09-08T16:17:03Z

A pi-acidic, totally synthetic HPLC chiral stationary phase is used to separate the enantiomers of a wide range of unsaturated P-chiral phosphine oxides. If allows for fast, sensitive and accurate e.e. determinations and secures easy access to opfically pure enantiomers by chromatography on preparative columns.

A BRANDI, S CICCHI, F GASPARRINI, F MAGGIO, C VILLANI, M KOPROWSKI, KM PIETRUSIEWICZ (1995) TETRAHEDRON-ASYMMETRY 6: 8 2017-2022

A NEW P-CHIRAL AMINOPHOSPHINE LIGAND CONTAINING A 2,2’-COUPLED PYRROLIDINE-PHOSPHOLANE RING-SYSTEM - SYNTHESIS AND COORDINATION PROPERTIES WITH RHODIUM(I) AND IRIDIUM(I) FRAGMENTS

2009-09-08T16:17:03Z

A new approach to the synthesis of chiral P,N-ligands containing a stereogenic phosphorus atom is reported; the synthesis, characterization and coordination properties of (PR, 2R, 3R, 2’R, 3’S, 4’S) 2[2’(3’,4’-di-tert-butoxy-1’-methyltetrahydropyrrolyl)]-3-methoxy-1-ph enyltetrahydrophosphole (P*-N-1), which contains a stereogenic phosphorus in addition to five contiguous stereocentr...

C BIANCHINI, S CICCHI, M PERUZZINI, KM PIETRUSIEWICZ, A BRANDI (1995) JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS : 8 833-834

A 5-MEMBERED ENANTIOPURE CYCLIC NITRONE FROM MALIC-ACID BY REGIOSELECTIVE OXIDATION OF CYCLIC HYDROXYLAMINE - SYNTHESIS OF (1S,7S,8AR)-OCTAHYDRO-1,7-DIHYDROXYINDOLIZINE

2009-09-08T16:17:03Z

The chiral optically pure five-membered 3-tert-butoxy-1-pyrroline N-oxide (1) was synthesized by a convenient five-step procedure from diethyl L-malate. The key step is the regioselective HgO dehydrogenation of the N-hydroxypyrrolidine 6 obtained by double-nucleophilic displacement of a (bis)mesylate with hydroxylamine. A rationalization of the observed regioselectivity of the oxidation by studyin...

S CICCHI, A GOTI, A BRANDI (1995) JOURNAL OF ORGANIC CHEMISTRY 60: 15 4743-4748

Optically active phosphine chalcogenides. 21. Assignment of the absolute configuration to enantiomeric 2,3-dihydro-1-phenyl-1H-phosphole 1-sulfides. X-ray structure of (+)-(1S,3aR,7S,8S,8aR,8bR)-7,8-di-tert-butoxy-1-phenyloctahydro-1H-pyrrolo[1,2-b]-1H-phospholo[2,3-d]isoxazole 1-sulfide.

2009-09-08T16:17:03Z

The structure and abs. configuration of the predominant I of the two diastereomeric 7,8-di-tert-butoxy-1-phenyloctahydro-1H-pyrrolo[1,2-b]phospholo[2,3-d]isoxazole 1-sulfides obtained in the kinetic resoln. expt. involving cycloaddn. reaction of (S,S)-3,4-di-tert-butoxy-3,4-dihydro-2H-pyrrole 1-oxide (1) with an excess of racemic 2,3-dihydro-1-phenyl-1H-phosphole 1-sulfide (2), was detd. by a sing...

K Michal Pietrusiewicz, Wanda Wieczorek, Stefano Cicchi, Alberto. Brandi (1994) Phosphorus, Sulfur Silicon Relat. Elem. 97: 233-8

ASSIGNMENT OF THE ABSOLUTE-CONFIGURATION TO ENANTIOMERIC 2,3-DIHYDRO-1-PHENYL-1H-PHOSPHOLE 1-SULFIDES - X-RAY STRUCTURE OF (+)-(1S,3AR,7S,8S,8AR,8BR)-7,8-DI(TERT-BUTOXY)-1-PHENYLOCTAHYDRO-1H-PYRR OLO[1,2-B]-1H-PHOSPHOLO[2,3-D]- ISOXAZOLE 1-SULFIDE

2009-09-08T16:17:03Z

The structure and absolute configuration of the predominant of the two diastereomeric 7,8-di-tert-butoxy-1-phenyloctahydro-1H-pyrrolo[1,2-b]phospholo[2,3- d]isoxazole 1-sulfides obtained in the kinetic resolution experiment involving cycloaddition reaction of (S,S)-3,4-di-tert-butoxy-3,4-dihydro-2H-pyrrole 1-oxide (I) with an excess of racemic 2,3-dihydro-1-phenyl-1H-phosphole I-sulfide (2), was d...

KM PIETRUSIEWICZ, W WIECZOREK, S CICCHI, A BRANDI (1994) PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 97: 1-4 233-238

SYNTHESIS OF LENTIGINOSINE BY STEREOSELECTIVE CHIRAL NITRONE CYCLOADDITION AND THERMAL REARRANGEMENT OF STRAINED SPIROISOXAZOLIDINE

2009-09-08T16:17:03Z

The total synthesis of Lentiginosine (3) is reported. The strategy is based on the 1,3-dipolar cycloaddition of a TBDPS protected 3,4-dihydroxypyrroline N-oxide to methylenecyclopropane followed by the thermal rearrangement of the resulting spirocyclopropaneisoxazolidine to give the functionalised indolizidine skeleton. The compound shows an [alpha](D) value identical, but opposite in sign, with t...

FM CORDERO, S CICCHI, A GOTI, A BRANDI (1994) Tetrahedron Letters 35: 6 949-952

KINETIC RESOLUTION IN 1,3-DIPOLAR CYCLOADDITION OF TARTARIC ACID-DERIVED NITRONES TO 2,3-DIHYDRO-1-PHENYL-1H-PHOSPHOLES - AN ENANTIOSELECTIVE APPROACH TO THE 2,2’-COUPLED PYRROLIDINE PHOSPHOLANE RING-SYSTEM

2009-09-08T16:17:03Z

Enantiomerically pure five-membered ring nitrones derived from L-tartaric acid via C2-symmetric O,O’-protected 3,4-dihydroxy pyrrolidines undergo highly regio- and stereoselective cycloaddition reactions with racemic 2,3-dihydro-1-phenyl-1H-phosphole 1-oxide and 1-sulfide. In all cases formation of only two diastereomeric cycloadducts is observed and their ratio (up to 10:1) is dependent on the ...

A BRANDI, S CICCHI, A GOTI, M KOPROWSKI, KM PIETRUSIEWICZ (1994) JOURNAL OF ORGANIC CHEMISTRY 59: 6 1315-1318

CHIRAL VINYL PHOSPHINE OXIDES - DOUBLE ASYMMETRIC INDUCTION IN THE 1,3-DIPOLAR CYCLOADDITION TO CHIRAL NITRONES - KINETIC RESOLUTION OF A RACEMIC PHOSPHOLENE OXIDE

2009-09-08T16:17:03Z

The 1,3-dipolar cycloaddition of nitrones with chiral vinylphosphine oxides or sulfides provides 5-phosphinyl substituted isoxazolidines with selectivity up to 99:1. Use of chiral nitrones allows a more generalized stereoselective synthesis of these compounds, also by means of a double asymmetric induction. With a racemic phospholene oxide, the high diastereofacial selectivity of the cycloaddition...

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ (1993) PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 75: 1-4 155-158

NEW SYNTHESIS OF 5-MEMBERED CYCLIC NITRONES FROM TARTARIC ACID

2009-09-08T16:17:03Z

S CICCHI, I HOLD, A BRANDI (1993) Journal of Organic Chemistry 58: 19 5274-5275

STEREOSELECTIVE NITRONE ADDITIONS TO VINYLPHOSPHINE DERIVATIVES - EFFECT OF PHOSPHORUS SUBSTITUENTS ON REACTION DIASTEREOSELECITIVITY

2009-09-08T16:17:03Z

Meaningful diastereofacial selectivity in cycloaddition of 2,2-dimethyl-3,4-pyrroline N-oxide (DMPO) to 12 structurally diversified vinylphosphine derivatives 1-12 has been achieved by proper choice of the polar substituent on phosphorus combined with effective steric differentiation of the remaining substituents. The unique sense of induction in all these reactions is consistent with the assumpti...

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ, M ZABLOCKA, W WISNIEWSKI (1991) JOURNAL OF ORGANIC CHEMISTRY 56: 14 4383-4388

SINGLE AND DOUBLE ASYMMETRIC INDUCTION IN THE CYCLOADDITION OF CHIRAL NITRONES TO ACHIRAL AND CHIRAL VINYLPHOSPHINE OXIDES

2009-09-08T16:17:03Z

The asymmetric 1,3-dipolar cycloadditions of the chiral alpha,beta-dialkoxynitrones (4S)-(Z)-N-(2,2-dimethyl-1,3-dioxolan-4-yl)methylenebenzylamineN-oxide 3 and (4S,5S)-(Z)-N-(2,2,5-trimethyl-1,3-dioxolan-4-yl) methylenebenzylamine N-oxide 4a to diphenylvinylphosphine oxide 2 give, besides complex mixtures of all the possible regio- and diastereoisomers, one major isomer, 5a and 8a respectively, c...

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ (1991) TETRAHEDRON-ASYMMETRY 2: 10 1063-1074

CRYSTAL-STRUCTURE AND STEREOCHEMISTRY OF (PS-STAR, 2S-STAR, 3AS-STAR)-HEXAHYDRO-2-(TERT-BUTYLVINYLTHIOPHOSPHINYL)-6,6-DIMETHYLPYRROL O[1,2-B]ISOXAZOLE

2009-09-08T16:17:03Z

The structure of the major product of the cycloaddition of 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five-membered heterocyclic rings. These rings were found to be two envelopes i...

KM PIETRUSIEWICZ, W WIECZOREK, S CICCHI, A BRANDI (1991) HETEROATOM CHEMISTRY 2: 6 661-664

REGIOSELECTIVE AND STEREOSELECTIVE SYNTHESES OF ISOXAZOLIDINES BEARING PHOSPHENYL SUBSTITUENTS

2009-09-08T16:17:03Z

The 1,3-dipolar cycloaddition of nitrones to vinylphosphine derivatives gives valuable new phosphinyl- and phosphino-substituted isoxazolidines also in optically pure form. A complete study of the regioselectivity and stereoselectivity of the cycloaddition is reported. Cycloaddition to chiral vinylphosphine derivatives allow the postulation of a transition state geometry able to explain the diaste...

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ (1991) GAZZETTA CHIMICA ITALIANA 121: 6 285-295

RADICAL-ADDITION TO VINYLPHOSPHINE OXIDES - 1,2-STEREOINDUCTION OF PHOSPHORUS STEREOGENIC CENTER

2009-09-08T16:17:03Z

Carbon centered radicals derived from reactions of halides 3-5 with Bu3SnH in the presence of AIBN have been trapped by diphenylvinylphosphine oxide 2 giving the addition products 6-8 in high yields. Free radical addition to 2 employing the Barton methodology gave lower yields. The use of chiral (racemic) vinylphosphine oxides allowed a stereoselective radical addition with a diastereomeric ratio ...

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ (1991) Tetrahedron Letters 32: 27 3265-3268

DIRECT SYNTHESIS OF ISOXAZOLIDINYLPHOSPHINES BY CYCLOADDITION OF NITRONES TO DIPHENYLPHOSPHINOETHENES AND X-RAY STRUCTURE OF 7,7-DIMETHYL-1-OXO-1-PHENYL-3-DIPHENYLPHOSPHINYL-HEXAHYDRO-1H-PYRROLO[ 1,2-C][1,3,2]OXAZAPHOSPHORINE

2009-09-08T16:17:03Z

The 1,3-dipolar cycloaddition reaction of N-alkyl nitrones with diphenylvinylphosphines affords directly isoxazolidinylphosphines in satisfactory yields and in regio- and stereoselective manner. The parent diphenylvinylphosphine was found to favor the formation of 5-phosphinoisoxazolidines whereas diphenylpropenylphosphine gave instead the 4-phosphinoisoxazolidine regioisomer. However, in reaction...

KM PIETRUSIEWICZ, I SALAMONCZYK, W WIECZOREK, A BRANDI, S CICCHI, A GOTI (1991) TETRAHEDRON 47: 43 9083-9096

NITRONE CYCLOADDITIONS TO 2,3-DIHYDRO-1-PHENYL-1H-PHOSPHOLE 1-OXIDE - DOUBLE ASYMMETRIC INDUCTION AND KINETIC RESOLUTION BY A CHIRAL NITRONE

2009-09-08T16:17:03Z

The cycloadditions of nitrones with 2,3-dihydro-1-phenyl-1H-phosphole 1-oxide give a single cycloadduct deriving from a highly diastereoselective approach of the nitrone anti to the phenyl ring of phospholene oxide. When the chiral gliceraldehyde derived nitrone is used, only two diastereoisomers are produced in 1.7:1 ratio. The structural assignment based on NMR data and X-ray analysis of the maj...

A GOTI, S CICCHI, A BRANDI, KM PIETRUSIEWICZ (1991) TETRAHEDRON-ASYMMETRY 2: 12 1371-1378

THE REGIOSELECTIVITY OF NITRONE CYCLOADDITIONS TO VINYL PHOSPHORUS-COMPOUNDS

2009-09-08T16:17:03Z

A BRANDI, S CICCHI, A GOTI, KM PIETRUSIEWICZ, W WISNIEWSKI (1990) TETRAHEDRON 46: 20 7093-7104

1,3-AMINOALCOHOLS BY REDUCTIVE CLEAVAGE OF ISOXAZOLIDINES WITH MOLYBDENUM HEXACARBONYL

2009-09-08T16:17:03Z

S CICCHI, A GOTI, A BRANDI, A GUARNA, F DESARLO (1990) Tetrahedron Letters 31: 23 3351-3354