Chemoenzymatic methods in the asymmetric synthesis of α-diazosulfoxides

Asymmetric synthesis of the sulfide lactones 12 and 13 in excellent enantiopurity is achieved by reduction of cyclohexanone derivative 10 using baker's yeast, followed by acid catalysed cyclisation.The outcome of the yeast reduction is very sensitive to the reaction conditions employed.Transformation of 12 to the α-diazosulfoxide 4 (≥98%ee) and rhodium acetate catalysed decomposition of this are also described.