Evidence for reversible intermediate formation in cyclopentenone cycloaddition

Abstract

The usual kinetics for product formation lead to variable values of kd, the rate constant for decay of the responsible triplet. On the assumption that at least one intermediate is formed which gives either products, or reverts to starting materials, a value near 108 s−1 is obtained for kd both from cyclopentene and hex-3-ene cycloadditions.