1,2-selective hydrosilylation of conjugated dienes

Selective 1,2-hydrosilylation of 1,3-dienes is a challenging problem to solve for transition metal catalysis. Butadiene, specifically, would be a useful substrate because 3-butenylsilane products have promise as superior coupling reagents for hybrid organic/inorganic materials synthesis. In this thesis, we describe the first selective 1,2-hydrosilylation of conjugated dienes, including butadiene.;Chapter 1 describes the relevance of organosilicon compounds to modern applications such as the synthesis of advanced materials and fine chemicals. The history and development of transition metal-catalyzed hydrosilylation methods are discussed, with emphasis on the current state of understanding of the mechanisms of late transition metal-catalyzed hydrosilylation. Known methodologies for the hydrosilylation of dienes and known 1,2-additions to dienes are discussed, highlighting the mechanistic features of these processes that informed the presented work.;In Chapter 2, novel research on the discovery and development of platinum catalysts for the 1,2-selective hydrosilylation of dienes is presented. Discovery of a cyclometallated platinum complex of tri-tert-butylphosphine as a precatalyst enabled the 1,2-selective hydrosilylation of conjugated dienes, including butadiene, isoprene, myrcene, and 2,3-dimethylbutadiene. Catalysis proceeds through a Pt(II)/Pt(IV) catalytic cycle and selectivity for 1,2-addition arises from coordinative saturation at catalyst intermediates that prevents formation of pi-allyl complexes. Data are presented that support the proposed Pt(II)/Pt(IV) mechanism and exclude more conventional Pt(0)/Pt(II) mechansims.