Silicone dendrons and dendrimers from orthogonal SiH coupling reactions

There are many potential applications for precise, large molecular weight silicone structures. The available elegant routes to silicone dendrimers are compromised by the use of reactions that involve acid/base formation: either type of catalyst can initiate silicone equilibration, which can lead to the loss of structural integrity of the dendrimers. Platinum-catalyzed hydrosilylation and B(C₆F₅)₃-catalyzed Piers Rubinsztajn reactions were shown to be orthogonal. Sequential utilization of the two reactions can be applied both convergently and divergently to prepare both silicone dendrons and dendrimers. Precise silicone compounds of molecular weights in excess of 13 500 g mol⁻¹ were prepared in good to excellent yield without the problems of degradative metathesis.