Auration of the sulfones MeSO2CH2CN and CH 2 (CH2SO2)2CH2

Article abstract of DOI:10.1515/znb-2005-0207

MeSO₂CH₂CN shows considerable C-H acidity at its methylene group. Through lithiation followed by reaction with (Ph ₃P)AuCl it can therefore be readily converted into the dinuclear, geminally substituted product MeSO₂C[Au(PPh₃)] ₂CN. With an excess of aurating reagents, a third [(Ph ₃P)Au] group becomes N-bonded to the nitrile unit to give an ionic trinuclear compound {MeSO₂C[Au(PPh₃)] ₂CNAu(PPh₃)}⁺BF₄^-. The same product is obtained by direct reaction of MeSO₂CH₂CN with [(Ph₃P)Au]BF₄. The crystal structures of the two products have been determined. The diaurated sulfone parts of the molecule and the cation are virtually superimposible. Small Au-C-Au angles and short Au-Au contacts suggest significant aurophilic interactions ("A-frame" structures). The small -C≡N-Au angle of 165.6(5)° in the cation indicates that the strong [(Ph₃P)Au]⁺ acceptor causes substantial changes in the bonding of the nitrile group. Dilithiation of 1,3-dithiane-S,S′-tetroxide followed by reaction with 2 equivalents of (Ph₃P)AuCl affords the geminally diaurated compound CH ₂(CH₂SO₂)₂C[Au(PPh ₃)]₂.