Base-Mediated Rearrangement of α-Dithioacetyl Propargylamines via Expansion of Dithioacetyl Ring: Synthesis of Medium-Sized S,S-Heterocycles.

Base-mediated rearrangement of 1,3-dithianyl-substituted propargylamines in DMF via expansion of the dithiane ring has been reported. The rearrangement provided 9-membered amino-functionalized sulfur-containing heterocycles (dithionine derivatives) in good yields under mild conditions. Propargylamines bearing 5-membered 1,3-dithiolane and 7-membered 1,3-dithiepane rings rearranged in a similar manner yielding 8- and 10-membered S,S-heterocycles, respectively.