Redox-chain decomposition of hydroxylamine-O-sulphonic acid. A novel general source of nucleophilic radicals for the functionalization of heteroaromatic bases

Abstract

Protonated heteroaromatic bases react with formamide, N,N-dimethylformamide, cyclic ethers, and methanol in the presence of hydroxylamine-O-sulphonic acid and catalytic amounts of an iron(II) salt to afford selective substitution by a redox chain process.