One pot simultaneous preparation of both enantiomer of β-amino alcohol and vicinal diol via cascade biocatalysis

Objectives: To investigate the efficiency of a new cascade biocatalysis system for the conversion of R, S-β-amino alcohols to enantiopure vicinal diol and β-amino alcohol.

Results: An efficient cascade biocatalysis was achieved by combination of a transaminase, a carbonyl reductase and a cofactor regeneration system. An ee value of > 99% for 2-amino-2-phenylethanol and 1-phenyl-1, 2-ethanediol were simultaneously obtained with 50% conversion from R, S-2-amino-2-phenylethanol. The generality of the cascade biocatalysis was further demonstrated with the whole-cell approaches to convert 10-60 mM R, S-β-amino alcohol to (R)- and (S)-diol and (R)- and (S)-β-amino alcohol in 90-99% ee with 50-52% conversion. Preparative biotransformation was demonstrated at a 50 ml scale with mixed recombinant cells to give both (R)- and (S)-2-amino-2-phenylethanol and (R)- and (S)-1-phenyl-1, 2-ethanediol in > 99% ee and 40-42% isolated yield from racemic 2-amino-2-phenylethanol.

Conclusions: This cascade biocatalysis system provides a new practical method for the simultaneous synthesis of optically pure vicinal diol and an β-amino alcohol.