Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols.

A change in mechanism was observed in the hypervalent iodine-mediated cyclization of -alkenylamides when the carbon chain between the alkene and the amide increased from two to three atoms. In the latter case, cyclization at the amide nitrogen to form the pyrrolidine ring was favored over cyclization at the amide oxygen. A DFT study was undertaken to rationalize the change in mechanism of this cyclization process.

Computationally Assisted Mechanistic Investigation into Hypervalent Iodine Catalysis: Cyclization of -Allylbenzamide.

Previous experimental work identified 2-iodoanisole as the best precatalyst for the oxidative cyclization of -alkenylamides into 2-oxazolines. Herein, we describe our investigation into the effect on the reaction rate based on the structure of the iodoarene precatalyst. We also reveal the mechanism of the cyclization based on DFT modeling and obtain a clear correlation between observed reaction rates and computationally derived activation energies for different iodoarenes.