Biocatalytic Approaches to the Henry (Nitroaldol) Reaction

Enantiopure beta-nitro alcohols are key chiral building blocks for the synthesis of bioactive pharmaceutical ingredients. The preparation of these target compounds in optically pure form has been the focus of much research and there has been an emergence of biocatalytic protocols in the past decade. For the first time, these biotransformations are the focus of this review. Herein, we describe two principal biocatalytic approaches to the Henry (nitroaldol) reaction. The first method is a direct enzyme-catalysed carboncarbon bond formation resulting in either an enantio-enriched or enantiopure beta-nitro alcohol. The second approach describes the Henry reaction without stereocontrol followed by a biocatalytic resolution to yield the enantiopure beta-nitro alcohol.