'Green' synthesis of nitro alcohols catalyzed by solid-supported tributylammonium chloride in aqueous medium

A series of 1-aryl-2-nitroalkan-1-ols (5a - m; Table 2) was prepared in yields of 64-94% by Henry reaction between aromatic aldehydes and nitroalkanes in the presence of a dual catalytic system of KOH and polystyrene-supported tributylammonium chloride (PsTBAC; 2). The reactions were performed either in H2O containing 10% of THF or, in the case of liquid reagents (aldehydes and nitroalkanes), in neat H2O at room temperature. The immobilized phase-transfer catalyst, designed to be used for large-scale industrial processes, could be easily separated from the products, and effectively re-used several times, basically without loss in activity.