Tuesday, March 31, 2020

When looking at strong bases resulting in E rxns why does the major product favor Hoffman if the LG is poor? Such as F. (Reluctance of the leaving group to leave deviates the mechanism from the synchronous E2: Abstraction of a proton by a base leads to accumulation of negative charge on the carbon (in a classical E2, the developing negative charge is immediately carried away by the leaving group). As a consequence, the reaction pathway is determined by the stability of a carboanion. The trend of stability of carbanions is the opposite to that of carbocations, that is the carbanion is more stable at the less substituted carbon. Therefore, the less substituted C=C is produced, which is against Zaitsev rule. - GS).

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