Synthesis of 1,2-Dihydroisoquinolines via Rhenium-catalyzed Tandem Cyclization and Nucleophilic Addition of 2-(1-Alkynyl)arylaldimines

A synthetic method for 1,2-dihydroisoquinolines via the 6-endo-dig cyclization of 2-alkynylaldimines and nucleophilic addition has been developed. When the 2-alkynylaldimines were reacted with various nucleophiles such as nitromethane, dimethyl malonate, phenylacetylene, hydrosilane, allylstannane, and ketene silyl acetal in the presence of a rhenium catalyst, the corresponding 1,2-dihydroisoquinolines were obtained in moderate to good yields.