TY - JOUR A1 - McKee, Michael L. A1 - Mlostoń, Grzegorz A1 - Urbaniak, Katarzyna A1 - Heimgartner, Heinz T1 - Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study JF - Beilstein Journal of Organic Chemistry PY - 2017/// VL - 13 SP - 410 EP - 416 SN - 1860-5397 DO - 10.3762/bjoc.13.44 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.13.44 KW - 1,3-dipolar cycloadditions KW - reaction mechanisms KW - reactive intermediates KW - thiocarbonyl S-methanides KW - thioketones N2 - An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of computational methods. The preferred formation of the unusual macroheterocycle, competitive with the 1,3-ring closure leading to a thiirane and the head-to-head dimerization yielding a 1,4-dithiane derivative, respectively, was explained based on the analysis of the structure of the favored conformer of the intermediate, delocalized diradical species. The influence of selenium as a ‘heavy atom’ for stabilization of this intermediate has been emphasized. ER -