Catalytic Reactions Involving Carbon-Halogen Bond Cleavage

Catalytic Reactions Involving Carbon-Halogen Bond Cleavage 

Catalytic reactions of organohalides using palladium, nickel, or rhodium catalysts are well investigated. Interestingly, however, in the case of ruthenium-catalyzed reactions, only a few examples involving carbon-halogen cleavage have been reported. 

An example of this is a Heck-type reaction of/3-bromostyrene with conjugated unsaturated ester using Ru(COD)(COT) as a catalyst (Eq. 9.66) [90]. 

During the past decade, several fundamental transformations of C-H bonds to other synthetically valuable bonds have been developed, and some basic applications of the catalytic functionalization of C-H bond to synthesis of polymers and the catalytic functionalization of natural products have been studied. During the next decade however, it is likely that fascinating developments will continue to be made in the direct use of C-H bonds in organic synthesis. 

Chatani, F. Kakiuchi, Pure Appl. Chem. 1997, 69, 589 (fj M. Sonoda, F. Kakiuchi, 

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Catalytic Reactions Involving Carbon-Halogen Bond Cleavage 251 9.6... 

The addition of an organopalladium intermediate to the double bond with subsequent cleavage of palladium hydride and restoration of unsaturation is the basis of another important process involving organopalladium compounds, the Heck reaction. In a catalytic version, the organopalladium intermediate is formed by oxidative addition to carbon-halogen or other carbon-heteroatom bonds, and the hydridopalladium complex is believed to be recycled by base-promoted reductive elimination (Scheme 5.7). 

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