Highly regioselective and rapid ring opening of the (methylenecyclopropyl)methyl radical

Abstract

Ring opening of the (2-methylenecyclopropyl)methyl radical ( 1) was studied by competition methods. Radical 1 rearranges of the 2-vinylallyl radical too fast to be trapped appreciably by thiophenol, but benzeneselenol trapping was possible. The rate constant for ring opening of 1 at 5 °C was k r = 3–4 × 10 9 s −1. The title radical ring opens to the 2-vinylallyl radical with a rate constant at 5 °C of 3–4 × 10 9 s −1.