Practical and Convenient Synthesis of <i>N</i>-Heterocycles: Stereoselective Cyclization of <i>N</i>-Alkenylamides with <i>t</i>-BuOI under Neutral Conditions

Abstract

[Structure: see text] tert-Butyl hypoiodite (t-BuOI) was found to be a powerful reagent for the cyclization of N-alkenylamides leading to a variety of N-heterocycles under extremely mild conditions. When N-alkenylsulfonamides were employed in the reaction, three- to six-membered saturated N-heterocycles were obtained in good to excellent yields with complete stereoselectivity. The method was applicable to the cyclization of alkenylbenzamide derivatives to afford N-, O- or N-, S-heterocycles.