Using an available compound 3 pentanone(1) as starting material, the key intermediate compound 4,6 dimethyl 3,7 nonandione(5) was synthesized through the addition elimination of silylenol ether and Michael addition of α methylene 3 pentanone(4) with silylenol ether(2). In the presence of chiral reagent 6 β phenyl amino 3 β,5α chlorestandiol(7), compound (5) was reduced by KBH 4 directly to give Tobacco Beetle Pheromone (7S) (-) 4,6 dimethyl 7 hydroxyl 3 nonanone(6). 25 D=-35 87°( c =0 23, CHCl 3), overall yield 23 9%.
