Preparation of p,p′-disubstituted-α,ω-diphenyl polyenes

Abstract

Condensation of appropriately substituted benzaldehydes or cmnnamaldehydes with either bis-Wittig reagents or bis-phosphonate esters (Homer-Emmons-Wadsworth modifications) containing one or two double bond units are general and quite efficient preparations of functionalized α,ω-diphenyl-polyenes containing 3, 4, 5, or 6 conjugated double bonds having all-E configurations. Bis-Wittig reagents prepared from tributyl rather than the more normally utilized triphenylphosphine are much more reactive, particularly for bis-condensations in which the benzaldehyde or cinnamaldehyde is substituted with electron-donating groups.