Baker's yeast mediated biohydrogenation of sulphur-functionalised methacrolein derivatives. Stereochemical aspects of the reaction and preparation ofthe two enantiomers of useful C-4 bifunctional chiral synthons

The baker's yeast mediated reduction of sulphur-functionalised methacrolein s 11, 15 and 18 leads to the preparation of the bifunctional methyl branche d C-4 chiral synthons 6 and 7. The stereochemical aspects of the biohydroge nation have been investigated. Both the oxidation state of sulphur and the isomeric position of the double bond affected the enantioselectivity of the reduction strongly, thus, offering access to the two enantiomeric forms of 6 and 7. (C) 2001 Elsevier Science Ltd. All rights reserved.