Scheme V and suggested that a more complex mechanism should be considered than had hitherto been hypothesized. From a mechanistic point of view, the fit question to answer was whether 16c was a byproduct or an intermediate in the formation of adduct 15c. To investigate this question, compound 16c was treated with benzyne under the same reaction conditions as above. The isolation of adduct 15c in 94% yield strongly suggests that 16c is ...
