The Synthesis of Chiral γ‐Lactones by Merging Decatungstate Photocatalysis with Biocatalysis

Abstract The implementation of light‐driven catalytic processes in biocatalysis opens a golden window of opportunities. We hereby report the merging of photocatalytic C−C bond formation with enzymatic asymmetric reduction for the direct conversion of simple aldehydes and acrylates or unsaturated carboxylic acids into chiral γ‐lactones. Tetrabutylammonium decatungstate (TBADT) is employed as the photocatalyst to trigger the hydroacylation of the starting olefins, yielding the corresponding keto esters/acids. Subsequently, an alcohol dehydrogenase converts the intermediate to the chiral alcohol, which undergoes lactonization to the desired γ‐lactone. The photochemoenzymatic synthesis of aliphatic and aromatic γ‐lactones was thereby achieved with up to >99 % ee and >99 % yield. This synthesis highlights the power of building molecular complexity by merging photocatalysis with biocatalysis to access high‐value added chiral compounds from simple, cheap and largely available starting materials.