Enantioconvergent Access to the Enantiomerically Pure Building Blocks (+)- or (-)-4-Hydroxy-3-methyl-2-cyclohexenone Using a Chemoenzymatic Process

A convenient chemoenzymatic enantioconvergent access to enantiomerically pure (+)- or (-)-4-hydroxy-3-methyl-2cyclohexenone is described using a one-pot two-step kinetic resolution-stereoinversion protocol followed by hydrolysis. The key step of the sequence is the spontaneous elimination of an undesired stereocenter. The choice between enzymatic acyl transfer or ester alcoholysis of the corresponding racemic starting material, together with the selectivity of a lipase, determines the absolute configuration of the desired single enantiomer.