Tuning lipase-catalysed kinetic resolution of 2-substituted thiophenes and furans: A scalable chemoenzymatic route to masked γ-bis-oxo-alcohols

Abstract

The demand for greener and applicable approaches aiming at the synthesis of optically active compounds as single enantiomers has seen a significant growth worldwide. Since most of the chemically synthesized compounds are produced as racemates their kinetic resolution has been of great interest. For this purpose a number of chemo-enzymatic approaches were proposed. One of such approaches, the use of isolated lipases, is a well-established alternative. Herein we report the kinetic resolutions of 2-Substituted five-membered heteroaromatic rings. By optimizing the reaction conditions it was possible to produce (2-hydroxy)-2-substituted furans and thiophenes in high enantiomeric ratio (E>200). Thus, racemic mixtures of compounds with slight structural differences were resolved. The current chemo-enzymatic strategy has been applied to a scalable approach leading to the formation of the enantiopure (S)-2i a well-known building block used for the synthesis of bioactive natural compounds.