SYNTHESES AND CRYSTAL-STRUCTURE OF 1-LITHIO-2,2-DIPHENYL-1-(PHENYLSULFONYL)ETHENE

Crystals of [1-lithio-2,2-diphenyl-1-(phenylsulfonyl)ethene]-N,N,N',N'-tetramethylethylethylenediamine (2/2)(2) were prepared by addition of BuLi to 1,1-diphenyl-2-(phenylsulfonyl)ethene (1) in the presence of N, N, N',N'-tetramethylethylenediamine (TMEDA) at low temperature. The X-ray structure analysis shows a centrosymmetric dimer bridged over an eight-membered (Li-O-S-O)(2) ring. There are no Li-C contacts to the C(alpha) atoms. Both Li cations ar tetracoordinated via the sulfonyl O-atoms and the N-atoms of the TMEDA ligand. The X-ray structure analysis of 1,1-diphenyl-2-(phenylsulfonyl)ethene (1) also was determined to compare interatomic distances and angles.