Asymmetric Synthesis of (R)‐3‐Hydroxy‐2‐methylpropanoate (‘Roche Ester’) and Derivatives via Biocatalytic CC‐Bond Reduction

Enoate reductases from the ‘old yellow enzyme’ family were employed for the asymmetric bioreduction of methyl 2‐hydroxymethylacrylate and its O ‐allyl, O ‐benzyl and O ‐TBDMS derivatives to furnish ( R )‐configurated methyl 3‐hydroxy‐2‐methylpropionate products in up to >99% ee Variation of the O ‐protective group had little influence on the stereoselectivity, but a major impact on the reaction rate.