Silver-catalyzed ring-opening of cyclopropenes: preparation of tertiary α-branched allylic amines

Herein we report a silver-catalyzed ring-opening of cyclopropenes by addition of amines. This transformation is thought to occur via an argentocarbenium intermediate and affords tertiary α-branched allylic amines in good yields and high regioselectivity. The protocol applies to various primary and secondary amines, as well as sterically hindered cyclopropenes. Friedel-Crafts cyclization of the cationic intermediate occurs as a competitive pathway to form methyl-indene.