A stereoselective synthesis of 1,6-diphenyl-1,3,5-hexatrienes utilising 4,4,6-trimethyl-2-vinyl-1,3,2-dioxaborinane as a two-carbon alkenyl building block

A number of 1,6-diphenyl-1,3,5-hexatrienes of varying alkene geometries were stereoselectively prepared from just two starting materials: iodobenzene and 4,4,6-trimethyl-2-vinyl-1,3,2-dioxaborinane via a series of Heck, Suzuki-Miyaura and stereocontrolled iododeboronation reactions. These results demonstrate how 4,4,6-trimethyl-2-vinyl-1,3,2-dioxaborinane can be used as a genuine two-carbon vinyl-dianion building block in stereocontrolled polyene synthesis.