Multiple-functionalizations of terminal alkynes with sodium sulfinates and tert-butyl nitrite: facile synthesis of 2H-azirines.

A new, catalyst-free tandem annulation route to 2,2-disulfonyl-2H-azirines via multiple-functionalizations of terminal alkynes with sodium sulfinates and tert-butyl nitrite is described. The use of sodium sulfinates and tert-butyl nitrite enables the formation of sulfonyl and NO radicals to selectively initiate and terminate the tandem annulation protocol, constituting a straightforward, conceptually different method to existing 2H-azirine synthesis techniques that currently require multiple steps by prior activation of the common starting materials.