Sequence-Controlled Catalytic One-Pot Synthesis of Siloxane Oligomers.

Silicones are highly valuable poly- and oligomeric materials with a broad range of applications due to their outstanding physicochemical properties. The core framework of silicone materials consists of siloxane (Si-O-Si) bonds, and thus, the development of efficient siloxane-bond-forming reactions has attracted much attention. However, these reactions, especially "catalytic" siloxane-bond-forming reactions that enable the selective formation of unsymmetrical siloxane bonds, remain relatively underdeveloped. On the other hand, controlled iteration has become a powerful tool for the sequence-controlled synthesis of poly- and oligomeric compounds. Recently, control over the siloxane sequence has been achieved by the one-pot iteration of a B(C6 F5 )3 -catalyzed dehydrocarbonative cross-coupling of alkoxysilanes with hydrosilanes and a B(C6 F5 )3 -catalyzed hydrosilylation of carbonyl compounds. Thus, it is now possible to generate linear, branched, and cyclic sequence-specific oligosiloxanes in a highly selective manner under chloride-free conditions.