Intramolecular 6-- Post-Ugi Cyclization of N-Substituted 2-Alkynamides: Direct Access to Functionalized Morpholinone Glycoconjugates.

We herein report a chemo- and regioselective 6- catalytic cyclization of Ugi adducts N-substituted 2-alkynamides to access functionalized morpholinone glycoconjugates in the presence of triphenylphosphine. This array allows an interesting multicomponent access to a library of functionalized morpholinone glycoconjugates under mild reaction conditions with regeneration of catalyst triphenylphosphine, supported by P nuclear magnetic resonance studies. Density functional theory shows the 6- oxocyclization pathway is preferred, which supports our experimental observation.