Hydroxylation of Dodecanoic Acid and (2R,4R,6R,8R)‐Tetramethyldecanol on a Preparative Scale using an NADH‐ Dependent CYP102A1 Mutant

Cytochrome P450 CYP102A1 from Bacillus megaterium is a fatty acid hydroxylase which catalyses the highly regioselective hydroxylation of branched fatty alcohols like (2R,4R,6R,8R)‐tetramethyldecanol (4). The product of this reaction (2R,4R,6S,8S)‐tetramethyldecane‐1,9‐diol (3) can be used in synthesis of macrolide antibiotics. For setting up the biooxidation process on a preparative scale a monophasic aqueous reaction system has been established. The system was optimised using an NADH‐dependent CYP102A1 mutant, dodecanoic acid as a model substrate and takes advantage of randomly methylated beta‐cyclodextrins for the solubilisation of hydrophobic substrates. In the reaction with 50 mM of dodecanoic acid a total turnover number of 66,700 and substrate conversion of 66.7 % could be reached. The total turnover number of a CYP102A1 mutant in the reaction with 23.4 mM (2R,4R,6R,8R)‐tetramethyldecanol 4 was 17,290 and substrate conversion reached 74 %. The reaction on a preparative scale yielded 420 mg of (2R,4R,6S,8S)‐tetramethyldecane‐1,9‐diol (3) in 60 % de. The major diastereomer 3a has the (2R,4R,6S,8S,9R)‐configuration. The configuration of 3a was determined by an X‐ray single crystal structure analysis of the corresponding bis‐dinitrobenzoate 5a.