10-UNDECENOIC ACID, AN INEXPENSIVE SOURCE FOR THE SYNTHESIS OF THE PHEROMONES OF COTTON PESTS, PEACH-TREE BORER AND CHERRY TREE BORER

The aldehyde 7, derived from 10-undecenoic acid (5) on cis-selective W ittig reaction with pentylidenetriphenylphosphorane, subsequent deprot ection and oxidation gave the pheromone (11Z)-hexadecenal (1). Wittig- Horner olefination of 1 with the phosphonate 9 furnished the conjugate d ester 10 which on base catalyzed isomerization to the (3Z)-ester 11 followed by LAH reduction and acetylation gave (3Z,13Z)-octadeadien-1- yl acetate (2). Compound 10 on the other hand was chemoselectively red uced and acetylated to furnish the pheromone (2E,13Z)-octadeadien-1-yl acetate (4). For the synthesis of (3E,13Z)-octadeadien-1-yl acetate ( 3), 1 was condensed with malonic acid under modified condition to affo rd the acid 13 which was converted to 3 by standard reaction protocol.