Origin of the Stereoselectivity in (Ethoxycarbonyl)‐, Cyano‐, and Phenyl‐Substituted (Arylsulfinyl)methyl Radicals

An explanation for the very high diastereoselectivity observed for the reactions of carbonyl‐substituted (arylsulfinyl)methyl radicals is presented, based on experimental results and semiempirical calculations. The influence of dipole‐dipole interactions, allylic 1,3‐strain ( A 1,3 strain), allylic 1,2‐strain ( A 1,2 strain), and coulombic interactions is discussed based on stereoselectivities observed with (alkoxycarbonyl)‐, cyano‐, and aryl‐substituted (arylsulfinyl)methyl radicals. In the second part, the effect of solvents and Lewis acids on the stereoselectivity of reactions of (arylsulfinyl)‐ and (alkylsulfinyl)benzyl radicals has been examined.