The activation of aminals and aminol ethers by sulfur dioxide and their reactions with electron rich aromatic compounds

Article abstract of DOI:10.1016/S0040-4020(97)00848-X

Reactions of bis(dialkylamino)methanes and ethoxydialkylaminomethanes with nucleophilic aromatic heterocycles in the presence of sulfur dioxide result in the formation of the expected Mannich bases in good yields. Reactions of phenols are similarly activated by sulfur dioxide which lead to improved regioselectivity: in particular the reactions of 2,5-dimethylphenol result in the formation of 2-dialkylaminomethyl-3,6-dimethylphenol whereas reaction occurs at the I-position using the classical procedures.