Facile synthesis of 1-aminoisoquinolines via the tandem reactions of 2-alkynylbenzaldoximes with isothiocyanates

A new, concise, and efficient route for the synthesis of 1-aminoisoquinolines in good to excellent yields is described; this involves the reaction of 2-alkynylbenzaldoximes and isothiocyanates, which is catalyzed by silver triflate in dichloromethane, at room temperature. This transformation involves tandem 6-endo cyclization, [3+2] cycloaddition, and subsequent rearrangement. The simple operational protocol provides a cost-effective, diversity-oriented route to 1-aminoisoquinolines under neutral, mild conditions.