Sulfonyl nitrenes from different sources: computational study of formation and transformations

Abstract

The formation of sulfonyl nitrenes RSO2N (R = Me, p-Tol, CF3) from different sources, such as sulfonyl azides RSO2N3, N-halosulfonamides RSO2NHHal, salts RSO2NNaCl, N-hydroxysulfonamides RSO2NHOH and sulfonylimino-λ3-iodanes ArI = NSO2R or -bromanes, by elimination of neutral molecules (N2, HCl, NaCl, H2O and ArHal, respectively) was studied theoretically at the density functional theory and second-order Møller-Plesset perturbation theory using the 6-311++G(d,p) and cc-pVTZ basis sets. The originally formed singlet nitrenes suffer nonradiative intersystem crossing to the triplet state (S1 ⇝ T1) or, sometimes, undergo spontaneous barrierless pseudo-Curtius rearrangement into the corresponding sulfonylamines RN = SO2. The activation barriers decrease in the order (kcal/mol): RSO2NHHal ~ RSO2NHOH (60–70) ≥ RSO2N(Na)Hal (40–50) > RSO2N3 (35) > RSO2N = IPh (9–13) ≥ RSO2N = BrC6H4CF3 (4–8). Copyright © 2013 John Wiley & Sons, Ltd.