Synthesis of polybenzyls by Suzuki Pd-catalyzed crosscoupling of boronic acids and benzyl bromides: Model reactions and polyreactions

Abstract

The palladium-catalyzed crosscoupling reaction of boronic acids and benzyl bromides can be used successfully for the preparation of benzyls in high yield. This C-C coupling reaction was optimized for the synthesis of polybenzyls by model reactions. Different reaction channels were observed here with meta- and para-bis(bromomethyl)benzenes. The main product with 1,3-bis(chloromethyl)benzene was the corresponding 1,3-dibenzylbenzene, but the main product with 1,4-bis(chloromethyl)benzene was the corresponding biaryl resulting from homocoupling of aromatic boronic acid. 1.3-Linked polybenzyls were synthesized based on the results of the model reactions. M̄n's of 2 380 corresponding to a DP of 26 were found based on GPC. No structural defects were detected within the limits of detection.