Polymer Skeletal Editing via Anionic Brook Rearrangements.

Abstract

This report communicates the first example of polymer backbone metamorphosis affected by anionic 1,2-Brook rearrangement of acyl silane moieties. Introduction of the acyl silane functionality into a polymer backbone was achieved via acyclic diene metathesis copolymerization (ADMET) of diene 1 and two dienes. We demonstrate that, using organolithium species and cyanide as nucleophiles, the backbones of resulting copolymers can be triggered to undergo highly efficient 1,2-Brook rearrangement, which transforms the poly(acyl silane)s into poly(silyl ether)s. Furthermore, the carbanion intermediate of the 1,2-Brook rearrangement can be intercepted by ketone electrophiles to give rise to polymers with quaternary stereogenic centers in the backbone and pendant functionality. Such structural editing of polymer backbones enables a new retrosynthetic paradigm for silicon-containing polymers that could not be accessed by traditional means.