Selective approach toward multifunctionalized lactams by lewis acid promoted PhSe group transfer radical cyclization.

We have developed a regiospecific and highly stereoselective strategy for constructing the five-/six-membered monocyclic and bicyclic nitrogen heterocycle skeletons using PhSe group transfer radical cyclization of alpha-phenylseleno amido esters promoted by a Lewis acid (e.g., Yb(OTf)(3)) under UV irradiation.

Synthesis of gamma-butyrolactams by photoinduced PhSe group transfer radical cyclization and formal synthesis of (+/-)-isocynometrine with diphenyldiselenide as promoter.

We have developed a strategy for constructing nitrogen heterocycles by photoinduced PhSe group transfer radical cyclization. trans-Alpha,beta-disubstituted gamma-butyrolactams (2-pyrrolidinones) were prepared in good yields (38-73%) with high regioselectivity and stereoselectivity from N-alkenyl alpha-PhSe beta-keto amides. Reaction outcomes were modulated by the steric effect of the substituents on the nitrogen atom of the cyclization precursors and the stereoelectronic effect of the substrates.