Ortho lithiation of N,N-dimethylbenzenesulfonamide by n-butyllithium. Condensation with electrophilic compounds

N,N-Dimethylbenzenesulfonamide was converted by n-butyllithium to the ortho-lithiosulfonamide, which was condensed with benzophenone, benzonitrile, phenylisocyanate, and carbon dioxide to form a carbinol, an imine, an amide, and an acid, respectively. The carbinol was cyclized thermally to give a sultone. The imine was converted to the corresponding ketone, oxime, and phenylhydrazone. The oxime underwent a Beckmann rearrangement to afford the same amide that was obtained in the reaction of the ortho-lithiosulfonamide with phenylisocyanate.