Synthetically versatile alkyl sulfinates
can be prepared from readily
available amines, using Katritzky pyridinium salt intermediates. In
a catalyst-free procedure, primary, secondary, and benzylic alkyl
radicals are generated by photoinduced or thermally induced single-electron
transfer (SET) from an electron donor–acceptor (EDA) complex,
and trapped by SO2 to generate sulfonyl radicals. Hydrogen
atom transfer (HAT) from Hantzsch ester gives alkyl sulfinate products,
which are used to prepare a selection of medicinal chemistry relevant
sulfonyl-containing motifs.