A NEW METHODOLOGY TO KEY INTERMEDIATES FOR SYNTHESIZING POLYENE COMPOUNDS

ω-Alkoxy-(2E,4E)-dienoates, ω-oxo-(2E,4E)-dienoates and δ-oxo-α,β:δ-dienones were prepared according to a new methodology shown in scheme I. High yield and high stereoselectivity were achieved by using transition metal catalyzed isomerization of ynoates or ynones instead of using Wittig-Horner-wadsworth-Emmons reaction to constitute the diene moiety. The usefulness of this methodology was demonstrated by the preparation of important synthetic precursors to polyene compounds and natural products such as 10-[(tetrahydropyran-2'-yl)Q xy]-(2E,4E)-decadienoates, methyl 8-[(tetrahydropyran-2'-yl)-o xy]-(2E,4E)-octadienoate, methyl 10-benzyloxy-(2E,4E)-decadienoate, 6-oxo-(2E,4E)-tetra-decadienal, methyl 8-oxo-(2E,4E)-octadienoate, and retrofractamide A. © 1990.