Baker's yeast mediated biohydrogenation of sulphur-functionalised methacrolein derivatives. Stereochemical aspects of the reaction and preparation of the two enantiomers of useful C4 bifunctional chiral synthons.

The baker's yeast mediated reduction of sulphur-functionalised methacroleins 11, 15 and 18 leads to the preparation of the bifunctional methyl branched C-4 chiral synthons 6 and 7. The stereochemical aspects of the biohydrogenation 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.