About the Li⊕ Gegenion Effect on α‐Sulfonyl Carbanions

To what extent do the structure and dynamics of the α‐sulfonyl carbanion l⊖ depend on the gegenion? As shown by the X‐ray structure analyses of the lithium‐ and tetrabutylammonium salts, these are present in the crystal as a dimer (1⊖/Li⊕ · 2THF)2with an eight‐membered (SOLiO)2ring and as a monomer 1⊕/NBu4 with discrete cations and anions, respectively. In contrast, the CαS rotation barrier of 1⊖ is hardly influenced by NBu (in THF or DMSO) and K⊕ (in DMSO). equation image