Oxy-functionalization Of Nucleophilic Rhenium(i) Metal Carbon Bonds Catalyzed By Selenium(Ⅳ)

摘要

Electrophilic C-H bond activation (CHA) with strong electro-philes, such as Pt~Ⅱ, Pd~Ⅱ, Au~Ⅲ, and Hg~Ⅱ, followed by reductive oxy-functionalization (OF) of the resulting positively polarized metal alkyl (M-R~(δ+)) intermediate is a well-known strategy for hydrocarbon hydroxylation. However, water and alcohol inhibition of the CHA reaction renders this strategy commercially impractical. We and others have shown that CHA with weakly electrophilic cations, such as Ir~Ⅲ and Ru~Ⅱ, are less prone to such inhibition. However, the reductive OF reactions utilized with highly electrophilic catalysts are generally not applicable to weakly electrophilic systems because the reduced oxidation potential thermodynamically disfavors reductive functionalization and/or the reduced electro-philicity can result in M-R~(δ-) polarized bonds that exhibit high barriers for nucleophilic attack at the carbon.6 Therefore we have set out to design new approaches for functionalization of M-R~(δ-) polarized bonds.