不活性炭素
水素結合切断を利用した有機合成の新手法
2004 年 62 巻 1 号 p. 14-26
詳細
2004 年 62 巻 1 号 p. 14-26
Catalytic addition of carbon-hydrogen bonds to olefins and acetylenes takes place with the aid of transition metal complexes. Coordination of a heteroatom to the metal is important for attaining both the C-H bond cleavage and the C-C bond formation.The C-C bond formations occur exclusively at the position ortho or the position β to the directing group. Various aromatic and olefinic compounds such as ketones, esters, aldehydes, imines, imidates, hydrazones, and nitriles can be used in this coupling reaction.The mechanistic studies of the ruthenium-catalyzed reaction of aromatic esters with olefins revealed that there is a rapid equilibrium prior to the C-C bond formation and the C-C bond formation is rate-determining. Catalytic arylation of C-H bond in aromatic ketones with organoboronates gave the ortho arylation products in high yield. The chelation-assisted C-H bond cleavage protocol is also applicable to the regioselective silylation of aromatic C-H bonds with hydrosilanes or vinylsilanes. Various aromatic and heteroaromatic compounds can be used in the silyaltion reaction.
