New and convenient synthesis of (Z)-heneicos-6-en-11-one, the douglas fir tussock moth (Orgyia pseudotsugata) sex pheromone, and (Z)-non-6-en-2-one, the immediate precursor for the synthesis of brevicomin, the sex attractant of the western pine beetle Dentroctonus brevicomis

Abstract

Convenient syntheses of (Z)-heneicos-6-en-11-one and (Z)-non-6-en-2-one were achieved from (Z)-1-nitrodec-4-ene and (Z)-1-nitrohept-4-ene. Solvent-free nitroaldol reaction of (Z)-1-nitroalkenes 1 with the aldehydes 2 on Amberlyst A-21, followed by in situ oxidation, gave the α-nitro ketones 3. Denitration viaρ-tolylsulphonylhydrazones and removal of the protecting group gave the title compounds 6a and 6b in 60 and 53% overall yield.