A new synthetic method for the preparation of secondary a-benzoyloxy aldehydes (5a-d) and its use in the stereoselective synthesis of conjugated (E,. E)-dienone (14) and dienoic esters (9b, 9c, 11, 15b, and 15c) were studied. Two-phase (benzene-H20) reaction of RCH2CHXCH0 (R= CH3, C3H7, C5Hl1, C7Hl5; X= C1, Br) with sodium benzoate (4) in the presence of a catalytic amount of tetrabutylammonium bromide gave the corresponding a- ...