Group 4 metal substituents hydride abstraction reactions

Hayes and Cooper have de.scribed abstraction reactions from a metal alkyl by an electrophilic reagent that goes by an SET route. Instead of the normal p abstraction of hydride from an ethyl group, which occurs in the usual electrtqihilic abstraction, he finds a preference for a abstraction from a methyl group. Since H atom abstraction usually takes place at the weakest C—H bond, the metal substituent presumably weakens the a- more than the jS-C—H bonds of the alkyl. 

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