ADH‐Catalyzed Biooxidation of (Hetero)aromatic sec‐Alcohols to Ketones Employing Vinyl Acetate as Acetaldehyde Surrogate

Abstract

The oxidation of sec‐alcohols is a common reaction in organic chemistry. We report a biocatalytic approach for oxidizing racemic (hetero)aromatic sec‐alcohols to the corresponding ketones. The reaction relies on employing freeze‐dried E. coli cells containing a recombinant variant of an alcohol dehydrogenase deduced from Lactobacillus kefir (E. coli/Lk‐ADH Prince) and vinyl acetate as an in situ acetaldehyde surrogate as oxidant. Biooxidations of a set of 20 racemic (hetero)aromatic alcohols were carried out in the presence of a catalytic amount of NADP+ cofactor, the biocatalyst, and vinyl acetate in an aqueous medium to generate the corresponding ketones with up to >99% conv. Preparative scale (1.0 mmol; 100 mM in 10 mL) reactions led to obtaining ketones in the 56−83% isolated yield range.