Enzyme Catalyzed Trans-Benzoin Condensation

Benzaldehyde lyase (BAL) is an enzyme that is used in the C-C bond cleavage and formation which was isolated first from Pseudomonas fluorescens Biovar I. It requires thiamine diphosphate (ThDP) and Mg(II) ions as cofactors. In this work, BAL was used as an enzymatic catalysis for the trans-benzoin condensation reaction between racemic benzoins and benzyloxyacetaldehyde to form unsymmetrical benzoin products with moderate enantiomeric excesses. ( S )-benzoin derivatives remained unreacted at the end of the reaction. In this enzymatic trans-benzoin condensation, benzyloxyacetaldeyhde acted as acceptor and different variety of racemic benzoin derivatives were used as donor and ( R )-2-hydroxy-1-phenylpropanone derivatives were synthesized up to 66% ee.