Understanding (the lack of) homolytic substitution chemistry of sulfones

Abstract

High level calculations suggest that homolytic substitution (S_H2) by alkyl radicals at sulfur proceeds through a mechanism that is assisted and dominated by LP → SOMO interactions; in the absence of these interactions, S_H2 chemistry at sulfur is predicted to be virtually impossible. G3(MP2)-RAD calculations suggest that cyclization of the tert-butylsulfonylbutyl radical 2 (n = 2) proceeds with a rate constant of 1.7 × 10⁻²⁴ s⁻¹ at 80°, some 28 orders of magnitude slower than its sulfide cousin (n = 0).