Stereoselective construction of the 1,1,1-trifluoroisopropyl moiety by asymmetric hydrogenation of 2-(trifluoromethyl)allylic alcohols and its application to the synthesis of a trifluoromethylated amino diol

The asymmetric hydrogenation of a series of 2-(trifluoromethyl)allylic alcohols 1a-g catalyzed by a BINAP-Ru(II) diacetate complex gave the corresponding products 2a-g in high yield (> 90% yield) and high diastereoselectivity (> 95% de). The asymmetric hydrogenation of 2-(trifluoromethyl) allylic alcohols provided an efficient stereoselective method to construct the 1,1,1-trifluoroisopropyl moiety. Based on the asymmetric hydrogenation of the 2-(trifluoromethyl) allylic alcohol 5a prepared by the reaction of (R)-2,2-dimethyl-1,3-dioxolane-4- carboxaldehyde with 3,3,3- trifluoroisopropenyllithium, (2R, 3S, 4R)-4-trifluoromethyl-1-aminopentane-2,3-diol 9 was synthesized in 36% overall yield over five steps. (c) 2007 Elsevier Ltd. All rights reserved.