Rh-catalyzed intramolecular cyclization of 1-sulfonyl-1,2,3-triazole and sulfinate. Concise preparation of sulfonylated unsaturated piperidines.

Graphical abstract Highlights • Strictly ordered scission and formation of a few bonds are attained in one flask. • Traditional S and new Rh chemistries elegantly collaborated to yield a new field. • Sulfur magic between its two exchangeable states leads an intriguing bond behavior. • Versatile unsaturated piperidines with N -sulfonyl protection are readily accessible. Abstract When 4-[3-(methanesulfinyloxy)propyl]-1-(arenesulfonyl)-1,2,3-triazoles were treated with rhodium catalysts of the type Rh 2 (RCO 2) 4 , a new intramolecular cyclization took place to afford 2,3-didehydro-1-(arenesulfonyl)-3-(methanesulfonyl)piperidines in good yields. This reaction most likely proceeds via a new reorganization of bonds in the same molecule, consisting of the addition of the sulfur atom of sulfinate ester to the α-(sulfonylimino)carbene moiety generated from the sulfonyltriazole, followed by the counter attack of the sulfonylimino nitrogen to the carbon bearing the oxygen terminus of sulfinate ester. [ABSTRACT FROM AUTHOR]