Metal-Free Oxidative Decarboxylative Heteroannulation of Alkynyl Carboxylic Acids with Sulfinates and tert-Butyl Nitrite toward 2,2-Disulfonyl-2H-Azirines

A new TBAF (tetrabutylammonium fluoride)-promoted TBHP (tert-butyl hydroperoxide)-mediated decarboxylative heteroannulation cascades of alkynyl carboxylic acids with sodium sulfinates and TBN (tert-butyl nitrite) has been developed for producing 2,2-disulfonyl-2H-azirines under metal-free conditions. By employing readily available tert-butyl nitrite as the nitrogen source, the method enable the formation of four new chemical bonds in a single reaction through decarboxylation, sulfonylatyion and nitrogen-incorporation annulation cascades, and provides an efficient access to disulfonylated 2H-azirines.