Reactions via C-H Bond Activation

Selective addition of alkenes and alkynes to aromatic compounds has also been performed by ruthenium-catalyzed aromatic C-H bond activation. Carbon-carbon bond formation occurs at the ortho positions of aromatic compounds, assisted by the neighboring functional group chelation. The reaction, catalyzed by RuH2(CO)(PPh3)3, was efficient with aromatic and heteroaromatic compounds, with various functional groups, and a variety of alkenes and alkynes [ 121 ] (Eq. 90). Activation of vinylic C-H bonds can occur in a similar manner. 

The sp2 C-H bond of aldehydes, formamides, or formate esters undergoes oxidative addition to ruthenium complexes to generate acylruthenium hydride, which can insert alkenes leading to the overall H-COR addition to alkenes [122] (Eq. 91). 

A ruthenium complex such as Ru3(CO)12 can activate the C-H bond of sp carbons on the condition that a neighboring functional group can coordinate to the metal to favor intramolecular C-H bond activation [123] (Eq. 92). 

Emerging reactions involving C-H bond activation with ruthenium catalysts are detailed in the corresponding chapter Activation of Inert C-H Bonds of this volume. 

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Synthetic Reactions via C-H Bond Activation C-C and C-E Bond Formation... 

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