Alkene Hydrosilation by a Cationic Hydrogen-Substituted Iridium Silylene Complex

摘要

The hydrosilation of olefins is the most versatile and technologically important reaction for formation of silicon-carbon bonds and is used to produce fine chemicals, chemical intermediates, and monomers, and to cross-link organosiloxane polymers. Despite these widespread applications, there is considerable interest in the development of improved hydrosilation catalysts which feature (for example) less expensive metals and/or more regioselective transformations. We recently identified a new type of hydrosilation mechanism that exhibits an unusually high degree of anti-Mark-ovnikov regioselectivity for olefin substrates. This reaction, which is currently associated only with the ruthenium silylene catalyst [Cp~*(~iPr_3P)H_2Ru=SiH(Ph)][B(C_6F_5)_4], operates via direct insertion of the olefin into the Si-H bond of the silylene ligand. This mechanism represents a new approach to hydrosilation that might allow extension to a wide range of substrates and conditions.