Reactivity Matching

REACTIVITY MATCHING

Having defined the types of commonly used carbon nucleophiles and carbon electrophiles, it would seem that if you react any of the carbon nucleophiles (electron donors) with any of the carbon electrophiles (electron acceptors), then a carbon–carbon bond should be formed. While this is theoretically true, it is unworkable from a practical point of view. If, for example, a carbanion nucle-ophile was reacted with a cationic electrophile, it is unlikely that the desired carbon–carbon bond formation would be detected, even after the smoke cleared. Or if a silyl enol ether nucleophile was reacted with an α, β-unsaturated ester, no reaction could be observed to take place in any reasonable time frame.

For carbon–carbon formation to be successful, the reactivities of the nucle-ophile and electrophile must be matched so that reaction occurs at a reasonable and controllable rate. Thus we must be able to easily generate both carbon nucle-ophiles and carbon electrophiles to be able to choose the appropriate partners for successful C–C bond formation.