title: Diversity in Gold-Catalyzed Formal Cycloadditions of Ynamides with Azidoalkenes or 2H-Azirines: [3+2] versus [4+3] Cycloadditions.
abstract: Gold-catalyzed cycloadditions of ynamides with azidoalkenes or 2H-azirines give [3+2] or [4+3] formal cycloadducts of three classes. Cycloadditions of ynamides with 2H-azirine species afford pyrrole products with two regioselectivities when the Cβ -substituted 2H-azirine is replaced from an alkyl (or hydrogen) with an ester group. For ynamides substituted with an electron-rich phenyl group, their reactions with azidoalkenes proceed through novel [4+3] cycloadditions to deliver 1H-benzo[d]azepine products instead.
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu 30013 (Taiwan).
authors.forename: Samir Kundlik
authors.initials: SK
authors.lastname: Pawar
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu 30013 (Taiwan).
authors.forename: Rajkumar Lalji
authors.initials: RL
authors.lastname: Sahani
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsinchu 30013 (Taiwan). rsliu@mx.nthu.edu.tw.
authors.forename: Rai-Shung
authors.initials: RS
authors.lastname: Liu
keywords: cycloaddition; gold; homogeneous catalysis; reaction mechanisms; structure elucidation