From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium‐Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction

Abstract The ruthenium‐catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning.We are indebted to the MINECO of Spain (RYC‐2011‐08451 and CTQ2013‐40591‐P), the Gobierno del Principado de Asturias (Project GRUPIN14‐006), and the COST Action SIPs‐CM1302 for financial support. J.G.‐A. thanks the MINECO and the European Social Fund for a "Ramón y Cajal" contract. E.L. acknowledges funding from the European Union's Horizon 2020 MSCA ITN‐EID program (grant agreement No 634200). N.R.‐L. acknowledges MINECO for funding under Torres‐Quevedo program (PTQ‐12‐05 407)