3,5-Dimethoxybenzaldehyde → 1-(3,5-Dimethoxyphenyl)-5-phenoxy-1-pentene

Participants

Reaction Steps

The triphenyl(4-phenoxybutyl)phosphonium bromide was converted to an ylide using n-butyllithium and refluxing with 3,5-dimethoxybenzaldehyde in ether for 3 hours gave 1-(3,5-dimethoxyphenyl)-5-phenoxy-1-pentene as a 2:1 mixture of E:Z isomers. Purification was by column chromatography and gave a 60% yield. Subsequently, hydrogenation of 1-(3,5-dimethyoxypheny)-5-phenoxy-1-pentene over palladium on carbon (10%) under 50 psi of hydrogen gas resulted in the quantitative reduction of the pentene carbon-carbon double bond in to yield 1-(3,5-dimethoxyphenyl)-5-phenoxy-1-pentane. This phenoxy-l-pentane was then contacted with boron tribromide in benzene for 72 hours at 25° C. to deprotect the methoxy groups of the compound and substitute the phenoxy moiety with bromide to form 5'-bromo olivetol. After purification, an 80% yield was achieved.

Provenance & Evidence