Bromoallenes as Allyl Dication Equivalents in the Absence of Palladium(0): Synthesis of Bicyclic Sulfamides by Tandem Cyclization of Bromoallenes

Abstract

Who needs a metal? A highly regioselective synthesis of cyclic sulfamides containing a bicyclo[3.3.0]octane skeleton has been developed (see scheme). The first intramolecular nucleophilic attack of the internal sulfamide nitrogen atom takes place at the central carbon atom of the allenic moiety, and is followed by a second intramolecular nucleophilic addition of the terminal sulfamide nitrogen atom to afford the bicyclic sulfamide.