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
A new and general method of iodine-mediated cyclization reactions of unsaturated carbamates, ureas and amides which gives N-cyclized products as a single regio-isomer was achieved. The present reaction proceeds in good yield through regio-control of an ambidentnucleophile by LiAl(Ot-Bu)4, and the regio-control (N-attack vs O-attack) was also found to be remarkably affected by the additive employed