Carbon-Carbon Bond Formation by the Use of Chloroiodomethane as a C1Unit. III. A Convenient Synthesis of the Mannich Base from Enol Silyl Ether by a Combination of Chloroiodomethane andN,N,N′,N′-Tetramethylmethanediamine

Abstract The Mannich dimethylaminomethylation of carbonyl compounds is conveniently carried out via enol trimethylsilyl ethers by a combination of chloroiodomethane (CH2ClI) and N,N,N′,N′-tetramethylmethanediamine (TMMD) in DMSO as the solvent at ambient temperature. The mechanism of the transformation is discussed on the basis of product analysis and 1H NMR spectral studies. The reagent system CH2ClI/TMMD also provides a convenient route to the Eschenmoser’s salt (Me2\overset+N=CH2,\overset−I).