Addition of Iodine Isocyanate to Olefins. Scope and Synthetic Utility

The stereospecific introduction of nitrogen functions via additions of iodine isocyanate to olefins is discusse with emphasis on the reagent, solvent effects, the scope of the reaction, the formation of carbamates, and synthetic routes to heterocyclic compounds and amino alcohols. Additions of iodine isocyanate generally proceed well with mono-, di-, and some trisubstituted olefins and can also be carried out with acetylenes. Conjugated unsaturated acids, esters, ketones, and nitriles are unreactive toward the reagent. Conjugated and nonconjugated dienes can yield monoaddition products. The β-iodo isocyanates can be characterized as carbamates, amine salts, or bisulfite addition compounds all of which can be transformed into aziridines. In this manner fused and spiroaziridines may be synthesized. The conversion of the isocyanate adducts to carbamates by exposure to alcohols can be sped up considerably by catalytic amounts of lithium or sodium alkoxide. The addition reaction may be employed for the stereospecific synthesis of cis-β-amino alcohols.