Cobalt-catalyzed dehydrative approach for the synthesis of unsymmetric disiloxanes and polysiloxanes

Conventional approaches to unsymmetric disiloxanes involve the condensation of silanol with hydroxy-, chloro-, or alkoxysilanes, which suffers from several limitations such as limited substrate scope, the requisite use of stoichiometric bases, expensive transition-metal catalysts, and typically unsatisfactory product selectivity. Herein, we report a dehydrative cobalt catalysis for unsymmetric disiloxane from two different silanols, which features a low loading of the earth-abundant cobalt catalyst, easy operation, good functional combinability, and gram-scale preparation. Notably, this approach also enables the facile preparation of unsymmetric polysiloxanes. A highly selective and scalable dehydrative approach for the synthesis of unsymmetric disiloxanes and polysiloxanes is reported using Earth-abundant cobalt catalyst under an air atmosphere.