Gold(I)-catalyzed rearrangement of aryl alkynylaziridines to spiro[isochroman-4,2 '-pyrrolines]

Alkynylaziridines carrying an aryl group could be efficiently converted to spiro[isochroman-4,2'-pyrrolines] with gold salts as catalysts. This new rearrangement involved a Friedel-Crafts type intramolecular reaction followed by cyclization of the aminoallene intermediate, both initiated by the dual sigma and pi Lewis acidities of gold.