Renewable Polyethers via GaBr3-Catalyzed Reduction of Polyesters

Herein, a novel approach is reported for the synthesis of medium- and long-chain aliphatic polyethers 2 based on the GaBr3-catalysed reduction of polyesters 1 with TMDS as the reducing agent. Thus, various linear and branched aliphatic polyesters 1 were prepared and systematically investigated for this reduction strategy, demonstrating the applicability and versatility of this new polyether synthesis protocol. Medium- and long-chain chain polyethers were obtained from the respective polyesters without or with minor chain degradation, whereas short-chain polyesters, such as poly-l-lactide 1i and poly[(R)-3-hydroxybutanoate] 1j, showed major chain degradation. In this way, previously unavailable and uncommon polyethers were obtained and studied.