An Annulation Reaction for the Synthesis of Morpholines, Thiomorpholines, and Piperazines from β-Heteroatom Amino Compounds and Vinyl Sulfonium Salts


  • M.Y. thanks the Higher Education Commission of Pakistan for support of a studentship. V.K.A. thanks the Royal Society for a Wolfson Research Merit Award and the EPSRC for a Senior Research Fellowship.


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Heterocycling: Diphenyl vinyl sulfonium salt 1 acts first as an electrophile, then a base, and then again as an electrophile in this operationally simple, high yielding, one-pot synthesis of pharmacologically important morpholines, thiomorpholines, and piperazines. Compound 1 is an excellent synthon for the 1,2-ethane dication.