Aldol Reactions by Lipase From Rhizopus niveus, an Example of Unspecific Protein Catalysis

Abstract

The lipase from Rhizopus niveus (RNL) catalyzed by unspecific protein catalysis the aldol reactions between cyclohexanone and aromatic aldehydes in organic solvents with water or aqueous buffer solution. The reactional conditions strongly influenced the yield (0–99%) and enantioselectivities in the anti-products (6–55% ee anti ). The aldol products with enantioselectivities in the anti-product were observed for inactive enzyme and in denaturing conditions. Therefore, the reactions in the evaluated conditions proceeded by unspecific protein catalysis with moderate enantioselectivities and not by promiscuous activity. These enzymatic studies identify a new green catalyst for aldol reactions and new possibilities for lipases, especially for the use of the lipase RNL, which has been scarcely reported in the literature and catalyzed the aldol reaction between different aromatic aldehydes and cyclohexanone.