Synthesis of difunctional initiator via the Peterson reaction

This paper presents an improved method to prepare divinylphenyl compounds which are a useful class of precursors in preparing difunctional organolithium initiators. In the past, most of the divinylphenyl compounds reported were prepared from reactions of phosphorus‐substituted carbanions with aldehydes and ketones (Wittig reaction). The phosphorus by‐product of the Witting reaction was difficult to be completely removed from the final products. In this paper, we apply the Peterson reaction (silane substituted carbanions) to the synthesis of divinylphenyl compounds. This reaction appears to be operationally simpler and cleaner than the Wittig reaction since the by‐product of silane is easily removed by silica Gel chromatography. The syn‐elimination of β‐hydroxylsilane is complete and clean under NaH condition with no detectable isomers in the final product. The reaction of the divinylphenyl compound with S‐butylithium forms a difunctional organolithium initiator which is used to prepare triblock copolymers with the desirable microstructure in each block.