Asymmetric Catalytic Hydrogenation toward a Value‐Added Chiral Building Block: Optically Active γ‐Butyrolactone Scaffold from Renewable and Synthetic Derived Feedstocks

This article provides a brief compendium on the production of chiral monocyclic γ‐lactone derivatives through asymmetric hydrogenation of keto acids and keto esters using different type of catalytic approaches: homogeneous, heterogeneous as well as chemoenzymatic. Homogeneous catalysis has always been ahead with this issue, addressing the problem from different perspectives, ranging from the use of transition metal complexes (i.e., Ru, Ir, Pd, and Ni) to ligand design (mainly phosphanes) to seeking a change in the nature of the process: a) direct hydrogenation using H 2 gas or b) transfer hydrogenation. This contrasts greatly with the scarce number of references found with heterogeneous catalysts, a fact that should be taken as an incentive for researchers, leaving a large field open to future research toward increasing both catalytic performance and recyclability. The integration of biocatalysis with synthetic chemistry is also an upward trend and opens up opportunities for the development of greener and more sustainable processes, due to the biogenicity/biodegradability of enzymes and to the mild reaction conditions. It is expected that continued advancements in genetic engineering and bioprocess optimization will drive further innovation and developments at a large scale, especially for stereoselective processes.