Philippe Bertus - Academia.edu (original) (raw)

Papers by Philippe Bertus

Research paper thumbnail of New Transformations from a 3-Silyloxy 2-Aza-1,3-diene: Consecutive Zr-Mediated Retro-Brook Rearrangement and Reactions with Electrophiles

Tetrahedron, 2000

... Vincent Gandon, Philippe Bertus and Jan Szymoniak Corresponding Author Contact Information , ... more ... Vincent Gandon, Philippe Bertus and Jan Szymoniak Corresponding Author Contact Information , E-mail The Corresponding Author. ... Process Res. Dev. 1998, 2, 49. (b) Lasarte, J.; Palomo, C.; Picard, JP; Dunogues, J.; Aizpurua, JM J. Chem. Soc., Chem. Commun. 1989, 72. ...

Research paper thumbnail of Asymmetric synthesis of the cyclopentanones related to NCS and N1999A2 antitumor antibiotics

Tetrahedron Letters, 2003

Optically pure protected mono- or dihydroxylated cyclopentanones, precursors for the core of the ... more Optically pure protected mono- or dihydroxylated cyclopentanones, precursors for the core of the antitumor antibiotics NCS and N1999A2, 1 and 2, were obtained in six to eight steps with excellent overall yields (up to 52%).

Research paper thumbnail of Reactivity of sugar α-aminonitrile derivatives under titanium-mediated cyclopropanation conditions

Tetrahedron, 2012

The reactivity of different sugar a-aminonitriles has been studied under titanium-mediated cyclop... more The reactivity of different sugar a-aminonitriles has been studied under titanium-mediated cyclopropanation conditions. This study has been performed on amide, lactam, and imide derivatives. It has been possible to obtain spiro[furanose-3,3 0-(3 0 ,5 0 ,6 0 ,7 0-tetrahydrospiro[cyclopropane-1,2 0-pyrrolo[1,2-a] imidazole])] derivatives.

Research paper thumbnail of Synthesis of a 5-Spirocyclopropyl Deoxyrhamnojirimycin as a Constrained Naringinase Inhibitor

Synthesis, 2007

A spirocyclopropyl analogue of deoxyrhamnojirimycin has been synthesized in 11 steps and 20% over... more A spirocyclopropyl analogue of deoxyrhamnojirimycin has been synthesized in 11 steps and 20% overall yield from L-arabinose. The key step of the reaction path involves titanium-mediated aminocyclopropanation of an L-arabinononitrile derivative. Improvements of the standard reaction conditions were investigated. The use of methyltitanium triisopropoxide as the titanium source allowed the reaction to take place at room temperature and afforded the corresponding cyclopropylamine in 80% yield.

Research paper thumbnail of Conversion of Imines into C,N-Dimagnesiated Compounds and Trapping with Electrophiles. One-Pot Access to 1-Azaspirocyclic Framework

Research paper thumbnail of Preparation and Some Synthetic Applications of 2-Hydroxyethyl-Substituted Cyclopropylamines

Synlett, 2008

ABSTRACT Primary cyclopropylamines bearing hydroxy side chains were obtained by Ti-mediated Coupl... more ABSTRACT Primary cyclopropylamines bearing hydroxy side chains were obtained by Ti-mediated Coupling of nitriles and homoallylic alcohols. Their usefulness as synthetic intermediates was demonstrated by the preparation of a constrained glutamic acid derivative and pyrrolizidine analogues.

Research paper thumbnail of Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles

Synlett, 2006

... Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles [... more ... Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles [1]. Chloé Tanguy a,b , Philippe Bertus a , Jan Szymoniak* a , Oleg V. Larionov b , Armin de Meijere* b. ... 14d Quiclet-Sire B, Quintero L, Sanchez-Jimenez G, Zard SZ,Synlett 2003, 75. ...

Research paper thumbnail of Diastereoselective Synthesis of trans -2-Substituted Cyclopropylamines

Synlett, 2006

ABSTRACT Upon treatment with n-butyllithium at -30 degrees C, the readily available trans-2-(trib... more ABSTRACT Upon treatment with n-butyllithium at -30 degrees C, the readily available trans-2-(tributylstannyl)-N,N-dibenzylcyclopropylamine undergoes tin-lithium exchange with retention of configuration, and trapping of the resulting aminocyclopropyllithium species with a range of electrophiles including alkyl and allyl bromides or iodides, disulfides, aldehydes and imines, affords the title compounds in moderate to good yields (69-89%).

Research paper thumbnail of Diene−Titanium Complexes as Synthetic Intermediates for the Construction of Three- or Five-Membered Carbocycles

Organic Letters, 2008

All reactions were conducted under an atmosphere of dry argon using standard Schlenk techniques. ... more All reactions were conducted under an atmosphere of dry argon using standard Schlenk techniques. Diethylether and THF were distilled from sodium benzophenone ketyl prior to use. Ti(Oi-Pr) 4 was used as received. Grignard reagents were prepared in Et 2 O from the corresponding bromide, and titrated in THF by menthol in the presence of orthophenanthroline. Cyanoesters 3a-c and cyanocarbonate 3d were prepared following reported procedures. 1 Flash chromatography was performed with silica gel 60 (Merck, 40-63 µm). 1 H and 13 C NMR spectra were recorded in CDCl 3 on a Bruker AC-250 or DRX-500 spectrometer. Chemical shifts were measured in (ppm) and coupling constants J in Hz (solvent peak reference: = 7.26 for 1 H, 77.0 for 13 C). IR spectra were recorded on a Nicolet Avatar 320 instrument. Mass spectra were recorded on a ThermoFinnigan Trace MS spectrometer. High Resolution Mass Spectra (HRMS) were performed on Q-TOF Micro micromass positive ESI (CV=30 V). 2.-Preparation of amines 1a-e 2.1-General procedure: To a solution of Ti(Oi-Pr) 4 (0.33 mL, 1.1 mmol) and the nitrile (1 mmol) in Et 2 O (5 mL) was added under argon at rt a solution of the homoallylic Grignard reagent (2.2 mmol, 0.5-1 M in Et 2 O). The mixture was stirred during 1 h, then 1 N HCl (ca 3 mL) and ethyl acetate (ca 15 mL) were added. NaOH (10% aq, ca 10 mL) was added and the

Research paper thumbnail of Studies on the titanium-catalyzed cyclopropanation of nitriles

Organic & Biomolecular Chemistry, 2005

The Ti-mediated reaction of Grignard reagents with nitriles was investigated with sub-stoichiomet... more The Ti-mediated reaction of Grignard reagents with nitriles was investigated with sub-stoichiometric amounts of titanium isopropoxide. Cyanoesters were converted to spirocyclopropanelactams in good yields using as low as 0.05 eq of Ti(O(i)Pr)4. Under similar conditions, cyanocarbonates led to spirocyclopropane oxazolidinones and/or aminocyclopropylcarbinols. A very short synthesis of the naturally occurring aminocyclopropanecarboxylic acid illustrates the usefulness of this methodology.

Research paper thumbnail of Evidence for the in situ formation of copper acetylides during Pd/Cu catalyzed synthesis of enynes: a new synthesis of allenynols

Research paper thumbnail of Specific solvent effect on R2ZrCl2 (R=butyl, ethyl) reactivity, a density functional study

Journal of Organometallic Chemistry, 2002

The reactivity of ZrCl 2 Bu 2 is modeled for the formation of ZrCl 2 (butene). Two pathways are c... more The reactivity of ZrCl 2 Bu 2 is modeled for the formation of ZrCl 2 (butene). Two pathways are computed: the band the g-Hydrogen migration. It is found that the b-H pathway is favored by about 13 kcal mol (1. The specific effect of dimethyl ether as a model of the THF solvent is analyzed and found to greatly facilitate the reaction. Solvent or ligand complexation on the zirconium is found more important in product ZrCl 2 (butene) than in the reagent ZrCl 2 Bu 2. These results are commented in regard to the experimental evidences of reactivity differences depending on the solvent used.

Research paper thumbnail of Synthesis of enynes and epoxyenynes by coupling: use of a new set of catalysts based on Pd–Ag salts

Journal of Organometallic Chemistry, 1998

The new couple of catalysts Pd(PPh 3) 4 and AgI are very efficient for the coupling of vinyltrifl... more The new couple of catalysts Pd(PPh 3) 4 and AgI are very efficient for the coupling of vinyltriflates and terminal alkynes in the presence of a bulky amine in dimethylformamide at room temperature. Enynes and epoxyenynes are obtained in good to excellent yields. As illustrated with several examples, a wide variety of functional groups are well tolerated in the described conditions. Silver acetylides have been proposed as intermediate in this reaction.

Research paper thumbnail of A Direct Synthesis of 1-Aryl- and 1-Alkenylcyclopropylamines from Aryl and Alkenyl Nitriles

The Journal of Organic Chemistry

The reaction of various aromatic nitriles with 1.1 equiv of Ti(Oi-Pr) 4 and 2.2 equiv of EtMgBr f... more The reaction of various aromatic nitriles with 1.1 equiv of Ti(Oi-Pr) 4 and 2.2 equiv of EtMgBr followed by addition of a Lewis acid gave 1-aryl cyclopropylamines in 43-76% yields. Under similar conditions, conjugated alkenenitriles afford 1-alkenylcyclopropylamines (42-65%).

Research paper thumbnail of A Versatile and Highly Stereoselective Access to Vinyl Triflates Derived from 1,3-Dicarbonyl and Related Compounds

The Journal of Organic Chemistry, 2008

SCHEME 1. Two Conventional Methods for the Synthesis of Vinyl Triflates from Ketones SCHEME 2. Di... more SCHEME 1. Two Conventional Methods for the Synthesis of Vinyl Triflates from Ketones SCHEME 2. Direct Route to Vinyl Triflates from Alkynes 10.

Research paper thumbnail of Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropylamines. Effect of Chelation on the Cyclopropanation Step

The Journal of Organic Chemistry, 2002

Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropy... more Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropylamines. Effect of Chelation on the Cyclopropanation Step.-The title reaction offers a new straightforward access to ON N-, and S-heterofunctionalized cyclopropylamines. A chelation effect appears to be responsible for spontaneous contraction of azatitanacycle intermediates to cyclopropylamines.-(BERTUS, PHILIPPE; SZYMONIAK,

Research paper thumbnail of A Straightforward Synthesis of Cyclopropanes from Aldehydes and Ketones

European Journal of Organic Chemistry, 2000

ABSTRACT

Research paper thumbnail of A Concise Stereoselective Synthesis of 2‐Substituted 1‐Aminocyclopropanecarboxylic Acids

European Journal of Organic Chemistry, 2009

A simple and stereoselective method for the preparation of (Z)‐2‐substituted 1‐aminocyclopropanec... more A simple and stereoselective method for the preparation of (Z)‐2‐substituted 1‐aminocyclopropanecarboxylic acids is described. The common key step for these reaction sequences involves the stereoselective Ti‐mediated coupling of benzyloxy nitrile and homoallylic alcohol. The resulting 2‐hydroxyethyl‐substituted cyclopropylamine can be transformed shortly into various cyclopropane amino acid analogues on the gram scale, in good overall yields. Several syntheses of 2,3‐methanoamino acids, that is, ACCs derived from proteinogenic α‐amino acids or analogues, such as glutamic acid, arginine, homoarginine, and lysine derivatives are presented to exemplify the usefulness of the method. Additionally, starting from cyanoesters, spirocyclopropane γ‐amino acid analogues are available in this way. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Research paper thumbnail of Cyclopropenylcarbinol Derivatives as New Versatile Intermediates in Organic Synthesis: Application to the Formation of Enantiomerically Pure Alkylidenecyclopropane Derivatives

Chemistry – A European Journal, 2009

The copper‐catalyzed carbomagnesiation (or hydrometalation) reaction of chiral cyclopropenylcarbi... more The copper‐catalyzed carbomagnesiation (or hydrometalation) reaction of chiral cyclopropenylcarbinol derivatives, obtained by means of a kinetic resolution of secondary allylic alcohols, leads to an easy and straightforward preparation of enantiomerically pure alkylidenecyclopropane derivatives. The reaction mechanism is composed of a syn‐carbometalation followed by a syn‐elimination reaction. To gain further insight into the reaction mechanism of the carbometalation, the diastereoselective formation of cyclopropylcarbinol was also achieved and was found to be very sensitive to the nature of the organometallic species used for the addition reaction. Cyclopropylcarbinol could also be prepared through a diastereoselective reduction of cyclopropenylcarbinol derivatives. Finally, functionalization of enantiomerically enriched cyclopropenylcarbinols into the corresponding acetate or phosphinite derivatives leads, under mild conditions, to various enantiomerically pure heterosubstituted a...

Research paper thumbnail of A direct conversion of α,β-unsaturated ketones to vinylcyclopropanes: new zirconium-mediated reaction

Chemical Communications, 2000

ABSTRACT

Research paper thumbnail of New Transformations from a 3-Silyloxy 2-Aza-1,3-diene: Consecutive Zr-Mediated Retro-Brook Rearrangement and Reactions with Electrophiles

Tetrahedron, 2000

... Vincent Gandon, Philippe Bertus and Jan Szymoniak Corresponding Author Contact Information , ... more ... Vincent Gandon, Philippe Bertus and Jan Szymoniak Corresponding Author Contact Information , E-mail The Corresponding Author. ... Process Res. Dev. 1998, 2, 49. (b) Lasarte, J.; Palomo, C.; Picard, JP; Dunogues, J.; Aizpurua, JM J. Chem. Soc., Chem. Commun. 1989, 72. ...

Research paper thumbnail of Asymmetric synthesis of the cyclopentanones related to NCS and N1999A2 antitumor antibiotics

Tetrahedron Letters, 2003

Optically pure protected mono- or dihydroxylated cyclopentanones, precursors for the core of the ... more Optically pure protected mono- or dihydroxylated cyclopentanones, precursors for the core of the antitumor antibiotics NCS and N1999A2, 1 and 2, were obtained in six to eight steps with excellent overall yields (up to 52%).

Research paper thumbnail of Reactivity of sugar α-aminonitrile derivatives under titanium-mediated cyclopropanation conditions

Tetrahedron, 2012

The reactivity of different sugar a-aminonitriles has been studied under titanium-mediated cyclop... more The reactivity of different sugar a-aminonitriles has been studied under titanium-mediated cyclopropanation conditions. This study has been performed on amide, lactam, and imide derivatives. It has been possible to obtain spiro[furanose-3,3 0-(3 0 ,5 0 ,6 0 ,7 0-tetrahydrospiro[cyclopropane-1,2 0-pyrrolo[1,2-a] imidazole])] derivatives.

Research paper thumbnail of Synthesis of a 5-Spirocyclopropyl Deoxyrhamnojirimycin as a Constrained Naringinase Inhibitor

Synthesis, 2007

A spirocyclopropyl analogue of deoxyrhamnojirimycin has been synthesized in 11 steps and 20% over... more A spirocyclopropyl analogue of deoxyrhamnojirimycin has been synthesized in 11 steps and 20% overall yield from L-arabinose. The key step of the reaction path involves titanium-mediated aminocyclopropanation of an L-arabinononitrile derivative. Improvements of the standard reaction conditions were investigated. The use of methyltitanium triisopropoxide as the titanium source allowed the reaction to take place at room temperature and afforded the corresponding cyclopropylamine in 80% yield.

Research paper thumbnail of Conversion of Imines into C,N-Dimagnesiated Compounds and Trapping with Electrophiles. One-Pot Access to 1-Azaspirocyclic Framework

Research paper thumbnail of Preparation and Some Synthetic Applications of 2-Hydroxyethyl-Substituted Cyclopropylamines

Synlett, 2008

ABSTRACT Primary cyclopropylamines bearing hydroxy side chains were obtained by Ti-mediated Coupl... more ABSTRACT Primary cyclopropylamines bearing hydroxy side chains were obtained by Ti-mediated Coupling of nitriles and homoallylic alcohols. Their usefulness as synthetic intermediates was demonstrated by the preparation of a constrained glutamic acid derivative and pyrrolizidine analogues.

Research paper thumbnail of Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles

Synlett, 2006

... Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles [... more ... Convenient Access to 2-Arylpyrroles from 2-Lithio-N,N-dibenzylcyclopropylamine and Nitriles [1]. Chloé Tanguy a,b , Philippe Bertus a , Jan Szymoniak* a , Oleg V. Larionov b , Armin de Meijere* b. ... 14d Quiclet-Sire B, Quintero L, Sanchez-Jimenez G, Zard SZ,Synlett 2003, 75. ...

Research paper thumbnail of Diastereoselective Synthesis of trans -2-Substituted Cyclopropylamines

Synlett, 2006

ABSTRACT Upon treatment with n-butyllithium at -30 degrees C, the readily available trans-2-(trib... more ABSTRACT Upon treatment with n-butyllithium at -30 degrees C, the readily available trans-2-(tributylstannyl)-N,N-dibenzylcyclopropylamine undergoes tin-lithium exchange with retention of configuration, and trapping of the resulting aminocyclopropyllithium species with a range of electrophiles including alkyl and allyl bromides or iodides, disulfides, aldehydes and imines, affords the title compounds in moderate to good yields (69-89%).

Research paper thumbnail of Diene−Titanium Complexes as Synthetic Intermediates for the Construction of Three- or Five-Membered Carbocycles

Organic Letters, 2008

All reactions were conducted under an atmosphere of dry argon using standard Schlenk techniques. ... more All reactions were conducted under an atmosphere of dry argon using standard Schlenk techniques. Diethylether and THF were distilled from sodium benzophenone ketyl prior to use. Ti(Oi-Pr) 4 was used as received. Grignard reagents were prepared in Et 2 O from the corresponding bromide, and titrated in THF by menthol in the presence of orthophenanthroline. Cyanoesters 3a-c and cyanocarbonate 3d were prepared following reported procedures. 1 Flash chromatography was performed with silica gel 60 (Merck, 40-63 µm). 1 H and 13 C NMR spectra were recorded in CDCl 3 on a Bruker AC-250 or DRX-500 spectrometer. Chemical shifts were measured in (ppm) and coupling constants J in Hz (solvent peak reference: = 7.26 for 1 H, 77.0 for 13 C). IR spectra were recorded on a Nicolet Avatar 320 instrument. Mass spectra were recorded on a ThermoFinnigan Trace MS spectrometer. High Resolution Mass Spectra (HRMS) were performed on Q-TOF Micro micromass positive ESI (CV=30 V). 2.-Preparation of amines 1a-e 2.1-General procedure: To a solution of Ti(Oi-Pr) 4 (0.33 mL, 1.1 mmol) and the nitrile (1 mmol) in Et 2 O (5 mL) was added under argon at rt a solution of the homoallylic Grignard reagent (2.2 mmol, 0.5-1 M in Et 2 O). The mixture was stirred during 1 h, then 1 N HCl (ca 3 mL) and ethyl acetate (ca 15 mL) were added. NaOH (10% aq, ca 10 mL) was added and the

Research paper thumbnail of Studies on the titanium-catalyzed cyclopropanation of nitriles

Organic & Biomolecular Chemistry, 2005

The Ti-mediated reaction of Grignard reagents with nitriles was investigated with sub-stoichiomet... more The Ti-mediated reaction of Grignard reagents with nitriles was investigated with sub-stoichiometric amounts of titanium isopropoxide. Cyanoesters were converted to spirocyclopropanelactams in good yields using as low as 0.05 eq of Ti(O(i)Pr)4. Under similar conditions, cyanocarbonates led to spirocyclopropane oxazolidinones and/or aminocyclopropylcarbinols. A very short synthesis of the naturally occurring aminocyclopropanecarboxylic acid illustrates the usefulness of this methodology.

Research paper thumbnail of Evidence for the in situ formation of copper acetylides during Pd/Cu catalyzed synthesis of enynes: a new synthesis of allenynols

Research paper thumbnail of Specific solvent effect on R2ZrCl2 (R=butyl, ethyl) reactivity, a density functional study

Journal of Organometallic Chemistry, 2002

The reactivity of ZrCl 2 Bu 2 is modeled for the formation of ZrCl 2 (butene). Two pathways are c... more The reactivity of ZrCl 2 Bu 2 is modeled for the formation of ZrCl 2 (butene). Two pathways are computed: the band the g-Hydrogen migration. It is found that the b-H pathway is favored by about 13 kcal mol (1. The specific effect of dimethyl ether as a model of the THF solvent is analyzed and found to greatly facilitate the reaction. Solvent or ligand complexation on the zirconium is found more important in product ZrCl 2 (butene) than in the reagent ZrCl 2 Bu 2. These results are commented in regard to the experimental evidences of reactivity differences depending on the solvent used.

Research paper thumbnail of Synthesis of enynes and epoxyenynes by coupling: use of a new set of catalysts based on Pd–Ag salts

Journal of Organometallic Chemistry, 1998

The new couple of catalysts Pd(PPh 3) 4 and AgI are very efficient for the coupling of vinyltrifl... more The new couple of catalysts Pd(PPh 3) 4 and AgI are very efficient for the coupling of vinyltriflates and terminal alkynes in the presence of a bulky amine in dimethylformamide at room temperature. Enynes and epoxyenynes are obtained in good to excellent yields. As illustrated with several examples, a wide variety of functional groups are well tolerated in the described conditions. Silver acetylides have been proposed as intermediate in this reaction.

Research paper thumbnail of A Direct Synthesis of 1-Aryl- and 1-Alkenylcyclopropylamines from Aryl and Alkenyl Nitriles

The Journal of Organic Chemistry

The reaction of various aromatic nitriles with 1.1 equiv of Ti(Oi-Pr) 4 and 2.2 equiv of EtMgBr f... more The reaction of various aromatic nitriles with 1.1 equiv of Ti(Oi-Pr) 4 and 2.2 equiv of EtMgBr followed by addition of a Lewis acid gave 1-aryl cyclopropylamines in 43-76% yields. Under similar conditions, conjugated alkenenitriles afford 1-alkenylcyclopropylamines (42-65%).

Research paper thumbnail of A Versatile and Highly Stereoselective Access to Vinyl Triflates Derived from 1,3-Dicarbonyl and Related Compounds

The Journal of Organic Chemistry, 2008

SCHEME 1. Two Conventional Methods for the Synthesis of Vinyl Triflates from Ketones SCHEME 2. Di... more SCHEME 1. Two Conventional Methods for the Synthesis of Vinyl Triflates from Ketones SCHEME 2. Direct Route to Vinyl Triflates from Alkynes 10.

Research paper thumbnail of Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropylamines. Effect of Chelation on the Cyclopropanation Step

The Journal of Organic Chemistry, 2002

Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropy... more Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropylamines. Effect of Chelation on the Cyclopropanation Step.-The title reaction offers a new straightforward access to ON N-, and S-heterofunctionalized cyclopropylamines. A chelation effect appears to be responsible for spontaneous contraction of azatitanacycle intermediates to cyclopropylamines.-(BERTUS, PHILIPPE; SZYMONIAK,

Research paper thumbnail of A Straightforward Synthesis of Cyclopropanes from Aldehydes and Ketones

European Journal of Organic Chemistry, 2000

ABSTRACT

Research paper thumbnail of A Concise Stereoselective Synthesis of 2‐Substituted 1‐Aminocyclopropanecarboxylic Acids

European Journal of Organic Chemistry, 2009

A simple and stereoselective method for the preparation of (Z)‐2‐substituted 1‐aminocyclopropanec... more A simple and stereoselective method for the preparation of (Z)‐2‐substituted 1‐aminocyclopropanecarboxylic acids is described. The common key step for these reaction sequences involves the stereoselective Ti‐mediated coupling of benzyloxy nitrile and homoallylic alcohol. The resulting 2‐hydroxyethyl‐substituted cyclopropylamine can be transformed shortly into various cyclopropane amino acid analogues on the gram scale, in good overall yields. Several syntheses of 2,3‐methanoamino acids, that is, ACCs derived from proteinogenic α‐amino acids or analogues, such as glutamic acid, arginine, homoarginine, and lysine derivatives are presented to exemplify the usefulness of the method. Additionally, starting from cyanoesters, spirocyclopropane γ‐amino acid analogues are available in this way. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Research paper thumbnail of Cyclopropenylcarbinol Derivatives as New Versatile Intermediates in Organic Synthesis: Application to the Formation of Enantiomerically Pure Alkylidenecyclopropane Derivatives

Chemistry – A European Journal, 2009

The copper‐catalyzed carbomagnesiation (or hydrometalation) reaction of chiral cyclopropenylcarbi... more The copper‐catalyzed carbomagnesiation (or hydrometalation) reaction of chiral cyclopropenylcarbinol derivatives, obtained by means of a kinetic resolution of secondary allylic alcohols, leads to an easy and straightforward preparation of enantiomerically pure alkylidenecyclopropane derivatives. The reaction mechanism is composed of a syn‐carbometalation followed by a syn‐elimination reaction. To gain further insight into the reaction mechanism of the carbometalation, the diastereoselective formation of cyclopropylcarbinol was also achieved and was found to be very sensitive to the nature of the organometallic species used for the addition reaction. Cyclopropylcarbinol could also be prepared through a diastereoselective reduction of cyclopropenylcarbinol derivatives. Finally, functionalization of enantiomerically enriched cyclopropenylcarbinols into the corresponding acetate or phosphinite derivatives leads, under mild conditions, to various enantiomerically pure heterosubstituted a...

Research paper thumbnail of A direct conversion of α,β-unsaturated ketones to vinylcyclopropanes: new zirconium-mediated reaction

Chemical Communications, 2000

ABSTRACT