Tetrahedron

2, 2, 6, 6-Tetramethylcyclohexanethione S-methylide, a highly hindered thiocarbonyl ylide: two-step cycloadditions

R Huisgen, H Giera, K Polborn

Index: Huisgen, Rolf; Giera, Henry; Polborn, Kurt Tetrahedron, 2005 , vol. 61, # 25 p. 6143 - 6153

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Citation Number: 25

Abstract

The switching from the concerted 1, 3-dipolar cycloaddition to a two-step pathway via zwitterionic intermediates requires a major energy difference between HOMO–LUMO energies of 1, 3-dipole and dipolarophile, as well as sterically demanding reactants. In contrast to previously studied models, the title compound, a thiocarbonyl ylide prepared by N2 extrusion from dihydrothiadiazole at 80° C, combined with 2, 3-bis (trifluoromethyl) ...