Enantiopure (S)-4-phenyl-3-butyn-2-ol and (S)-1-phenyl-2-butanol through an enzymatic reduction

This paper describes an enzymatic approach to producing (S)-4-phenyl-3-butyn-2-ol [(S)-3] and (S)-1-phenyl-2-butanol [(S)-4] from their corresponding ketones. W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (W110A TeSADH), a Prelog mutant of TeSADH, is used as a biocatalyst in this approach. The enantioselective reduction of α,β-alkynyl ketone 4-phenyl-3-butyn-2- one produced (S)-3 in an excellent yield and high levels of both chemo- and enantio-selectivities keeping the alkynyl moiety intact. The reduction of 1-phenyl-2-butanone (2) produced (S)-4 of higher enantioselectivity than that observed previously in the W110A TeSADHcatalyzed reduction of phenylacetone, a ketone with one methylene unit less than compound 2.