초록
<P><B>Abstract</B></P><P>In contrast to the widely studied asymmetric bioreduction of α,β‐unsaturated carboxylic acid esters catalyzed by ene‐reductases, the reaction applied to lactones remains unexplored. A broad set of ene‐reductases was found to reduce various α‐, β‐ and γ‐substituted α,β‐unsaturated butyrolactones to yield the corresponding saturated non‐racemic lactones. Substitution patterns greatly influenced activities and stereoselectivities and lactone products were obtained in moderate to excellent yields; importantly, enzyme‐based stereocontrol allowed access to both enantiomers in up to >99% <I>ee</I>. Chiral recognition of a distant γ‐center led to kinetic resolution with remarkable enantioselectivities (E values up to 49). An unprecedented case of dynamic kinetic resolution was observed with 3‐methyl‐5‐phenylfuran‐2(5<I>H</I>)‐one, whereby spontaneous racemization of the substrate furnished the product in up to 73% conversion and >99% <I>ee</I> and 96% <I>de</I>.</P>