Saverio Florio - Academia.edu (original) (raw)
Papers by Saverio Florio
Organic Letters, 2006
[reaction: see text] A stereoselective synthesis of 9,10-epoxy-1,6-dioxa-4,7-diazaspiro[4,5]decan... more [reaction: see text] A stereoselective synthesis of 9,10-epoxy-1,6-dioxa-4,7-diazaspiro[4,5]decanes has been developed on the basis of the addition of beta-lithiated oxazolinyloxiranes to nitrones. Conversion of these spirocyclic derivatives into 4,5-epoxy-1,2-oxazin-6-ones and successively into alpha,beta-epoxy-gamma-amino acids, alpha-hydroxy-gamma-amino acids, and gamma-butyrolactams is described.
The Journal of Organic Chemistry, 2001
Lithiooxiranes 3a and 3b, generated by deprotonation of oxiranes 2a and 2b with s-BuLi at -100°C
Synthesis, 2001
... Lithiation of 2-(1-Chloroethyl)-2-oxazolines: Synthesis of Substituted Oxazolinyloxiranes and... more ... Lithiation of 2-(1-Chloroethyl)-2-oxazolines: Synthesis of Substituted Oxazolinyloxiranes and Oxazolinylaziridines. Vito Capriati a , Leonardo Degennaro a , Saverio Florio* a , Renzo Luisi a , Carmela Tralli a , Luigino Troisi b. ... p.184-187. 5a Meyers AI, Collington EW,J. Am. Chem. ...
Chemistry-a European Journal, 2010
Organic Letters, 2002
Stereospecific -lithiation of -aryl-substituted oxazolinyloxiranes is described. The trapping rea... more Stereospecific -lithiation of -aryl-substituted oxazolinyloxiranes is described. The trapping reaction of such reactive intermediates with carbonyl compounds gave r, -epoxy-γ-butyrolactones after deblocking of the oxazoline moiety. This methodology has been also extended to the synthesis of optically active r, -epoxy-γ-butyrolactones.
Tetrahedron, 2005
The preparation of N-substituted oxazolinylaziridines and their deprotonation to afford the corre... more The preparation of N-substituted oxazolinylaziridines and their deprotonation to afford the corresponding aziridinyllithiums is described. The chemical and configurational stability of the lithiated species depends on the N-substituent on the aziridine ring. The trapping with carbonyl compounds of (R*,S*) configurated oxazolinylaziridines is an interesting route for the preparation of functionalised a,b-aziridino-g-lactones. q
Tetrahedron Letters, 1998
2-Oxiranyl and 2-aziridinyl thiazoles 3 and 7 have been prepared by lithiation of thiazoles 1a an... more 2-Oxiranyl and 2-aziridinyl thiazoles 3 and 7 have been prepared by lithiation of thiazoles 1a and 1b and reaction with α-halogenocarbonyl compounds [1a, 1c-d] and α-halogenoimines [1b], respectively.
European Journal of Organic Chemistry, 2000
Abstract Propargylic oxiranes 4a− e and aziridines 8a− c have been prepared from cinnamyl chlorid... more Abstract Propargylic oxiranes 4a− e and aziridines 8a− c have been prepared from cinnamyl chloride through lithiation− alkylation with α-halo carbonyl compounds and α-chloro imines, respectively. The reaction with substituted α-halo carbonyl compounds and α-chloro ...
Cheminform, 2007
The regioselective lithiation of terminal oxazolinylaziridines has been investigated. The steric ... more The regioselective lithiation of terminal oxazolinylaziridines has been investigated. The steric hindrance of the nitrogen substituent in 1-trityl-2-oxazolinylaziridine 3a, combined with the coordinating ability of the oxazolinyl group, causes beta-lithiation, whereas a completely regioselective alpha-lithiation is observed with the much less sterically demanding 1-benzyl-2-oxazolinylaziridine 3c and a competition between alpha- and beta-lithiation occurs with 1-cumyl-2-oxazolinylaziridine 3b in which the N-substituent has a steric hindrance in between the trityl and the benzyl groups. The application of the lithiation-trapping sequence for the preparation of enantioenriched 2,3-cis-disubstituted oxazolinylaziridines and aziridino-gamma-lactones is also reported.
Organic Letters, 2007
[structure: see text]. The lithiation reaction of cis- and trans-N-alkyl-2,3-diphenylaziridines h... more [structure: see text]. The lithiation reaction of cis- and trans-N-alkyl-2,3-diphenylaziridines has been investigated. While cis-diphenylaziridines do not undergo any lithiation upon treatment with organolithiums, the lithiation reaction of the trans counterparts is completely alpha-regioselective and the stereochemical course of the lithiation-trapping sequence is solvent dependent: inversion of configuration in coordinating solvents (THF or toluene/crown ether) and retention in hexane, ether, or toluene. The preparation of stereodefined functionalized N-alkyl-2,3-diphenylaziridines is described.
The Journal of Organic Chemistry, 2008
The R-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMED... more The R-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMEDA), taking place with a stereochemistry which dramatically depends on the solvent coordinating ability (inversion of configuration in THF and retention in toluene), has been carefully investigated. 1 H, 13 C, and 7 Li multinuclear NMR investigations at low temperature suggest that two differently configured lithiated aziridines (monomeric cis-1-Li in THF and dimeric trans-1-Li in toluene) are involved.
Tetrahedron Letters, 2000
Boron and titanium azaenolates 2 and 4, generated at 0°C and −100°C, respectively, from the optic... more Boron and titanium azaenolates 2 and 4, generated at 0°C and −100°C, respectively, from the optically active chloromethyloxazoline 1, have been found to couple with aliphatic ketones in a highly diastereoselective fashion ending up with the formation of optically active oxazolinyl oxiranes 3. Less stereoselective was the reaction with aromatic ketones.
Tetrahedron, 1999
Lithiated chloromethyl derivatives2a-d, available by deprotonation of 2-(chloromethyl)-1,3-benzot... more Lithiated chloromethyl derivatives2a-d, available by deprotonation of 2-(chloromethyl)-1,3-benzothiazole1a, -1,3-oxazoline1b, -pyridine1c and -quinoline1d, react with carbonyl compounds to give chlorohydrins3a-g and then epoxides4a-g upon treatment withNaOH/iPrOH. The same chlorohydrins3a-g could be converted into heterosubstituted chloroalkenes5a-g with very highEstereoselection upon reaction withMeSO/2ClEt3N
Journal of Organic Chemistry, 1995
Like oxiranes, aziridines are highly strained compounds.' The ring strain makes them susceptible ... more Like oxiranes, aziridines are highly strained compounds.' The ring strain makes them susceptible to ringopening reactions that dominate their chemistry and give them the ability to act as useful synthetic intermediates for the preparation of a great variety of organic compounds, such as alkaloids,2 amino acids,3 aminosugars: antibiotics: aminophosphonic acids: homoallylic amines,' labeled propynylglycine,s (tosy1amino)carbonyl comp o u n d~,~ and pyrrolidines.1°
Directed ortho-Lithiation of N-Alkylphenylaziridines. -The title compound (I) undergoes smooth or... more Directed ortho-Lithiation of N-Alkylphenylaziridines. -The title compound (I) undergoes smooth ortho-lithiation at the phenyl ring and, thus, a variety of arylaziridines, phthalans and phthalides are prepared. The N-alkyl analogues (XXa) and (XXb) are also reactive, whereas no results can be obtained with the sterically hindered substrates (XXc) and (XXII). The Boc-substituted aziridine (XXIII) affords only the rearranged product XXIV). -(CAPRIATI, V.; FLORIO*, S.; LUISI, R.; MUSIO, B.; Org. Lett. 7 (2005) 17, 3749-3752; Dip. Farm.-Chim., Univ. Bari, I-70126 Bari, Italy; Eng.) -R. Steudel
Tetrahedron Letters, 1996
α,β-epoxy aldehydes have been prepared by deblocking of oxazolinyl oxiranes, which in turn have b... more α,β-epoxy aldehydes have been prepared by deblocking of oxazolinyl oxiranes, which in turn have been synthesized on treatment of 4,4-dimethyloxazolinylchloromethyllithium with aldehydes.
Chemistry-a European Journal, 2010
Organic Letters, 2006
[reaction: see text] A stereoselective synthesis of 9,10-epoxy-1,6-dioxa-4,7-diazaspiro[4,5]decan... more [reaction: see text] A stereoselective synthesis of 9,10-epoxy-1,6-dioxa-4,7-diazaspiro[4,5]decanes has been developed on the basis of the addition of beta-lithiated oxazolinyloxiranes to nitrones. Conversion of these spirocyclic derivatives into 4,5-epoxy-1,2-oxazin-6-ones and successively into alpha,beta-epoxy-gamma-amino acids, alpha-hydroxy-gamma-amino acids, and gamma-butyrolactams is described.
The Journal of Organic Chemistry, 2001
Lithiooxiranes 3a and 3b, generated by deprotonation of oxiranes 2a and 2b with s-BuLi at -100°C
Synthesis, 2001
... Lithiation of 2-(1-Chloroethyl)-2-oxazolines: Synthesis of Substituted Oxazolinyloxiranes and... more ... Lithiation of 2-(1-Chloroethyl)-2-oxazolines: Synthesis of Substituted Oxazolinyloxiranes and Oxazolinylaziridines. Vito Capriati a , Leonardo Degennaro a , Saverio Florio* a , Renzo Luisi a , Carmela Tralli a , Luigino Troisi b. ... p.184-187. 5a Meyers AI, Collington EW,J. Am. Chem. ...
Chemistry-a European Journal, 2010
Organic Letters, 2002
Stereospecific -lithiation of -aryl-substituted oxazolinyloxiranes is described. The trapping rea... more Stereospecific -lithiation of -aryl-substituted oxazolinyloxiranes is described. The trapping reaction of such reactive intermediates with carbonyl compounds gave r, -epoxy-γ-butyrolactones after deblocking of the oxazoline moiety. This methodology has been also extended to the synthesis of optically active r, -epoxy-γ-butyrolactones.
Tetrahedron, 2005
The preparation of N-substituted oxazolinylaziridines and their deprotonation to afford the corre... more The preparation of N-substituted oxazolinylaziridines and their deprotonation to afford the corresponding aziridinyllithiums is described. The chemical and configurational stability of the lithiated species depends on the N-substituent on the aziridine ring. The trapping with carbonyl compounds of (R*,S*) configurated oxazolinylaziridines is an interesting route for the preparation of functionalised a,b-aziridino-g-lactones. q
Tetrahedron Letters, 1998
2-Oxiranyl and 2-aziridinyl thiazoles 3 and 7 have been prepared by lithiation of thiazoles 1a an... more 2-Oxiranyl and 2-aziridinyl thiazoles 3 and 7 have been prepared by lithiation of thiazoles 1a and 1b and reaction with α-halogenocarbonyl compounds [1a, 1c-d] and α-halogenoimines [1b], respectively.
European Journal of Organic Chemistry, 2000
Abstract Propargylic oxiranes 4a− e and aziridines 8a− c have been prepared from cinnamyl chlorid... more Abstract Propargylic oxiranes 4a− e and aziridines 8a− c have been prepared from cinnamyl chloride through lithiation− alkylation with α-halo carbonyl compounds and α-chloro imines, respectively. The reaction with substituted α-halo carbonyl compounds and α-chloro ...
Cheminform, 2007
The regioselective lithiation of terminal oxazolinylaziridines has been investigated. The steric ... more The regioselective lithiation of terminal oxazolinylaziridines has been investigated. The steric hindrance of the nitrogen substituent in 1-trityl-2-oxazolinylaziridine 3a, combined with the coordinating ability of the oxazolinyl group, causes beta-lithiation, whereas a completely regioselective alpha-lithiation is observed with the much less sterically demanding 1-benzyl-2-oxazolinylaziridine 3c and a competition between alpha- and beta-lithiation occurs with 1-cumyl-2-oxazolinylaziridine 3b in which the N-substituent has a steric hindrance in between the trityl and the benzyl groups. The application of the lithiation-trapping sequence for the preparation of enantioenriched 2,3-cis-disubstituted oxazolinylaziridines and aziridino-gamma-lactones is also reported.
Organic Letters, 2007
[structure: see text]. The lithiation reaction of cis- and trans-N-alkyl-2,3-diphenylaziridines h... more [structure: see text]. The lithiation reaction of cis- and trans-N-alkyl-2,3-diphenylaziridines has been investigated. While cis-diphenylaziridines do not undergo any lithiation upon treatment with organolithiums, the lithiation reaction of the trans counterparts is completely alpha-regioselective and the stereochemical course of the lithiation-trapping sequence is solvent dependent: inversion of configuration in coordinating solvents (THF or toluene/crown ether) and retention in hexane, ether, or toluene. The preparation of stereodefined functionalized N-alkyl-2,3-diphenylaziridines is described.
The Journal of Organic Chemistry, 2008
The R-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMED... more The R-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMEDA), taking place with a stereochemistry which dramatically depends on the solvent coordinating ability (inversion of configuration in THF and retention in toluene), has been carefully investigated. 1 H, 13 C, and 7 Li multinuclear NMR investigations at low temperature suggest that two differently configured lithiated aziridines (monomeric cis-1-Li in THF and dimeric trans-1-Li in toluene) are involved.
Tetrahedron Letters, 2000
Boron and titanium azaenolates 2 and 4, generated at 0°C and −100°C, respectively, from the optic... more Boron and titanium azaenolates 2 and 4, generated at 0°C and −100°C, respectively, from the optically active chloromethyloxazoline 1, have been found to couple with aliphatic ketones in a highly diastereoselective fashion ending up with the formation of optically active oxazolinyl oxiranes 3. Less stereoselective was the reaction with aromatic ketones.
Tetrahedron, 1999
Lithiated chloromethyl derivatives2a-d, available by deprotonation of 2-(chloromethyl)-1,3-benzot... more Lithiated chloromethyl derivatives2a-d, available by deprotonation of 2-(chloromethyl)-1,3-benzothiazole1a, -1,3-oxazoline1b, -pyridine1c and -quinoline1d, react with carbonyl compounds to give chlorohydrins3a-g and then epoxides4a-g upon treatment withNaOH/iPrOH. The same chlorohydrins3a-g could be converted into heterosubstituted chloroalkenes5a-g with very highEstereoselection upon reaction withMeSO/2ClEt3N
Journal of Organic Chemistry, 1995
Like oxiranes, aziridines are highly strained compounds.' The ring strain makes them susceptible ... more Like oxiranes, aziridines are highly strained compounds.' The ring strain makes them susceptible to ringopening reactions that dominate their chemistry and give them the ability to act as useful synthetic intermediates for the preparation of a great variety of organic compounds, such as alkaloids,2 amino acids,3 aminosugars: antibiotics: aminophosphonic acids: homoallylic amines,' labeled propynylglycine,s (tosy1amino)carbonyl comp o u n d~,~ and pyrrolidines.1°
Directed ortho-Lithiation of N-Alkylphenylaziridines. -The title compound (I) undergoes smooth or... more Directed ortho-Lithiation of N-Alkylphenylaziridines. -The title compound (I) undergoes smooth ortho-lithiation at the phenyl ring and, thus, a variety of arylaziridines, phthalans and phthalides are prepared. The N-alkyl analogues (XXa) and (XXb) are also reactive, whereas no results can be obtained with the sterically hindered substrates (XXc) and (XXII). The Boc-substituted aziridine (XXIII) affords only the rearranged product XXIV). -(CAPRIATI, V.; FLORIO*, S.; LUISI, R.; MUSIO, B.; Org. Lett. 7 (2005) 17, 3749-3752; Dip. Farm.-Chim., Univ. Bari, I-70126 Bari, Italy; Eng.) -R. Steudel
Tetrahedron Letters, 1996
α,β-epoxy aldehydes have been prepared by deblocking of oxazolinyl oxiranes, which in turn have b... more α,β-epoxy aldehydes have been prepared by deblocking of oxazolinyl oxiranes, which in turn have been synthesized on treatment of 4,4-dimethyloxazolinylchloromethyllithium with aldehydes.
Chemistry-a European Journal, 2010