Françoise Escale

Viable use of 2-substituted thiazolidine-4-methanol diastereoisomeric mixtures during asymmetric borane reduction of aromatic ketones

Abstract The reduction of aromatic ketones by borane in the presence of the inseparable diastereoisomeric mixture of 2-substituted thiazolidine-4-methanol has been investigated. Modest to high enantiomeric excesses were obtained increasing with thiazolidine steric hindrance.

(S)-(3-Hydroxy-4,4-dimethyl-2-oxopyrrolidin-1-yl) acetic acid as a solid supported chiral auxiliary in the asymmetric synthesis of β2-homoarylglycines

Abstract Diastereoselective additions of the resin-supported ( S )-(3-hydroxy-4,4-dimethyl-2-oxopyrrolidin-1-yl) acetic acid to phthalimidomethyl aryl ketenes allow solid phase preparation of β 2 -homoarylglycines with reasonable degrees of stereoselectivity.

New synthesis of enantiomerically pure (S)-3-amino-2-phenyl propanoic acid via the asymmetric transformation of its racemic N-phthaloyl derivative

Abstract The synthesis of racemic N-phthalyl 3-amino-2-phenyl propanoic acid and its asymmetric transformation via the corresponding prochiral ketene have been investigated, allowing the preparation of enantiomerically pure (S)-3-amino-2-phenyl propanoic acid.

Synthesis of N-boc-(R)-α-phenyl-γ-aminobutyric acid using an in situ diastereoselective protonation strategy

Abstract The synthesis of (±)-N-phthalyl α-phenyl-γ-aminobutyric acid and its asymmetric transformation via ketene formation have been investigated, allowing, after hydrolysis and amine protection, the preparation of the enantiomerically pure N-Boc-(R)-α-phenyl-γ-aminobutyric acid.

Diastereoselective esterification of (±)-N-trifluoroacetyl pipecolic acid using (S)-α-methyl pantolactone: synthesis of (S)-N-Boc pipecolic acid and (S)-N-Boc-2-piperidinemethanol

Abstract Racemic N -trifluoroacetyl pipecolic acid has been converted into ( S )- N -Boc-pipecolic acid or ( S )- N -Boc-2-piperidinemethanol by DCC/DMAP-induced diastereoselective esterification with ( S )-α-methyl pantolactone, followed by a saponification or a reduction reaction and N -Boc protection.

First asymmetric synthesis of (R)-(−)-α-phenyl δ-amino valeric acid

Abstract An efficient synthesis of the ( R )-(−)-α-phenyl δ-amino valeric acid 1 is described starting from commercially available compounds. The key intermediate in this synthesis is the corresponding totally protected prochiral ketene.

STEREOSELECTIVE BORANE REDUCTION OF ACETOPHENONE USING 1,3,2-OXAZABOROLIDINE DERIVED FROM (R)-4-(DIPHENYLHYDROXYMETHYL)-1,3-THIAZOLIDINE

Abstract A new chiral 1, 3, 2-oxazaborolidine derived from (R)-4-(diphenylhydroxymethyl)-l, 3-thiazolidine has been synthesized and its efficiency in the asymmetric reduction of acetophenone by borane has been investigated. It gives (R)-l-phenylethanol with high enantiomeric excess