Preparation of ketones from esters via substituted cyclopropanols. Application to the synthesis of (+/-)-ipsenol, (+/-)-ipsdienol and amitinol, the components of aggregation pheromones of the Ips bark beetles

The regioselective two-step sequence of bromination-dehydrobromination of 2 -(2,2-diethoxy)-1-methyl-1-cyclopropanol affords 3-(2,2-dietboxyethyl)-3-bu ten-2-one in high yield. The reduction of the latter, followed by chlorinat ion and dehydrochlorination, provides 2-(2,2-diethoxyethyl)-1,3-butadiene t hat was used as a building block for the synthesis of (+/-)-ipsenol, (+/-)- ipsdienol and amitinol - the components of aggregation pheromones of the Ip s bark beetles. (C) 1999 Elsevier Science Ltd. All rights reserved.