Baker's-yeast-mediated reduction of sulfur-containing compounds

Both the efficiency and the stereoselectivity in baker's-yeast-mediated reduction of ketones are strongly influenced by both the presence and the position of sulfur substituents, or indeed by the use of sulfur-containing additives. Interestingly the oxidation level of the sulfur substituent has a powerful impact on the outcome of the yeast reduction. It is apparent that use of the sulfone moiety as a substituent to influence the efficiency and stereoselectivity in ketone reduction is substantially more effective than use of the analogous sulfide and sulfoxide moieties. Stereochemical control in the baker's yeast reduction of ketones through the introduction of sulfur functional groups (sulfides, sulfoxides and sulfones) or sulfur-containing additives has attracted considerable attention. This microreview provides a summary of developments to date, highlighting the synthetic utility of the yeast-mediated ketone reduction influenced by the presence of sulfur moieties.