We present a new asymmetric synthesis of b-hydroxycarboxylic acids from ketones, performed by carboxylation using CO 2 followed by asymmetric hydrogenation. First, the carboxylation of ketones gives b-ketocarboxylic acids. The effects of temperature, reaction time, and amount of 1,.0]undec-7-ene (DBU) promoter on the carboxylation were investigated. The DBU can be recycled. For the second step, the asymmetric hydrogenation of these b-ketocarboxylic acids, we determined the effect of solvent choice, H 2 pressure, and substrate substitution. Hydrogenation yield and enantioselectivity are solvent-dependent, and the mechanism could proceed through hydrogenation of either the enol or the keto forms of the bound substrate. This synthesis is industrially advantageous due to the limited number of reactants required, their low-cost, and the potential for recycling unused materials.

Hydroxycarboxylic acids (ether carboxylic acids) and esters Q 0450β-Hydroxycarboxylic Acids from Simple Ketones by Carboxylation and Asymmetric Hydrogenation. -The yield of the hydrogenation step and the enantioselectivity are solvent-dependent. The method is industrially advantageous due to the limited number of reactants required, their low-cost and the ability to recycle the DBU reagent and any unused ketone. -(FLOWERS, B. J.; GAUTREAU-SERVICE, R.; JESSOP*, P. G.; Adv. Synth. Catal. 350 (2008) 18, 2947-2958; Dep. Chem., Queen's Univ., Kingston, Ont. K7L 3N6, Can.; Eng.) -Bartels 18-088