Reactions in which carbon-cobalt bonds are cleaved

Reactions in which carbon-cobalt bonds are cleaved 

The area of carbon-cobalt bond cleavage reactions is of perhaps the greatest direct relevance to the mechanism of action of the B,2 coenzymes. Thus, while it is not yet clear if new organocobalt intermediates are formed (and decomposed) from substrates and the cobalt-containing moiety of adenosylcobalamin during the enzyme-catalyzed intramolecular rearrangements (see Section 4), it is clear that the activation of adenosylcobalamin, as well as the coenzymic action of methylcobalamin require that the carbon-cobalt bond of the coenzymes be cleaved. 

In a general sense, carbon-cobalt bond cleavage can occur by any one of three mechanisms mode I cleavage (Eqn. 31) 

As there are reasonably well documented cases of each of these three modes of bond cleavage we can deal with each independently. 

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