Dearomative Indole Cycloaddition Reactions of Aza-Oxyallyl Cationic Intermediates: Modular Access to Pyrroloindolines

A regioselective dearomative aza-(3 + 2) cycloaddition reaction of substituted indoles with α-halohydroxamates has been developed. This transformation provides rapid access to highly functionalized pyrroloindolines that are represented in large number of bioactive compounds. The natural product, physostigmine, has been concisely synthesized utilizing this method.