Stereoelectronic effects in conformations of sulfide, sulfoxide, and sulfone α-carbanions

Energy and stabilization of conformers of α-carbanions of sulfides, sulfoxides, and sulfones are calculated, where the most stable conformations in sulfide and sulfone α-carbanions are at 180°, which benefit from strong nC−→σ*S-C stereoelectronic effects (91 and 59 kJ/mol). An nC−→σ*S-O interaction (79 kJ/mol) stabilizes the sulfoxide's minimum conformation at 60°.