STEREOSELECTIVE SYNTHESES OF BETA,GAMMA-UNSATURATED ESTERS AND GAMMA-LACTONES - L-1-YL)-3-(DIPHENYLPHOSPHORYL)-1-ETHOXY-1-PROPENE, A PROTECTED =CCH2CO2ET SYNTHON EQUIVALENT

ol-1-yl)-3-(diphenylphosphoryl)-1-ethoxy-1-propene (3), prepared from N-(alpha-ethoxy-allyl)benzotriazole (1), underwent selective Horner re actions with aldehydes to give substituted dienes. Subsequent hydrolys is of these intermediates readily produced beta,gamma-unsaturated este rs 2a-c in good yields. Similar reactions with ketones followed by hyd rolysis of 10 produced, depending on the conditions, either the corres ponding gamma,gamma-disubstituted beta,gamma-unsaturated esters 11a-d or gamma-lactones 9a-c and 13. A double lithiation process provided be ta,gamma,gamma-trisubstituted beta,gamma-unsaturated esters 15, 18, an d beta,gamma,gamma-trisubstituted gamma-lactone 14.