Regiocontrolled Iodoaminocyclization Reaction of an Ambident Nucleophile Mediated by Basic Metallic Reagent

A new and general method of iodine-mediated cyclization reactions of allyl or homoallyl carbamates, ureas, and amides was found to give N-cyclized products as single regioisomers. The present reaction proceeded in good yield through regiocontrol (N-cyclization > O-cyclization) and the increase in the reactivity of an ambident nucleophile by a basic metallic reagent. The N-cyclization selectivity was remarkably affected by the additive employed. The iodoaminocyclization reaction of the homoallyl carbamates and ureas with a chiral center at the homoallylic position was found to proceed with high 1,3-cis- and 1,3-trans-selectivity, respectively.