Specific β-Scission of 3β,5-Cyclocholestan-6-yl radical

Abstract

The 3β,5-cyclo-5β-cholestan-6-yl radical (6), generated by interaction of triphenylstannane with 6β-chloro-3β,5-cyclo-5β-cholestane (12), undergoes β-scission by specific fission of the 4,5-bond to give the thermodynamically less stable possible radical product (8). The results of these and earlier experiments indicate that β-scission of cyclopropylcarbinyl radicals is under stereoelectronic control, and involves a transition state formed by primary interaction of the semi-occupied orbital with a βγ-σ* orbital.