Asymmetric Synthesis of (3R,5R)-3-((tert-Butyldimethylsily)oxy)-5-((Z)-2-Bromovinyl)-Tetrahydro-Furan-2-one,an Intermediate for the Synthesis of Fostriecin

(3R,5R)-3-((tert-Butyldimethylsily)oxy)-5-((Z)-2-bromovinyl)-tetrahydro-furan-2-one, an intermediate for the synthesis of Fostriecin was achieved by intramolecular asymmetric induction in propene addition of (-)-8-phenylmenthyl glyoxylate followed by inversion of C3-hydroxyl group and Sharpless asymmetric dihydroxylation with simultaneous cyclization to give lactone 5. Then protection of C3-hydroxyl group and oxidation of the C6-primary hydroxyl group which reacted with Wittig reagent to yield the target compound 4.

Asymmetric syntheses of α-amino acids via double chiral induction in alkylation of the ketimine derived from 2-hydroxypinan-3-one and menthyl glycinate

Asymmetric syntheses of (S)-α-amino acids in 28--98% optical yields via double chiral induction in alkylations of ketimine 1 derived from (+)-2-hydroxypinan-3-one and (-)-men- thyl glycinate which is a chiral match pair have been studied. The factors controlling the diastereoselec- tivities in alkylation reactions of the ketimine, the properties of alkylating agents and various alkylation conditions are examined.