A PdI2/I2-catalyzed thiolation-annulation route of alkynes with azides and disulfides for the synthesis of 4-sulfenylisoquinolines is described. This route allows numerous 2-alkynylbenzyl azides to react with disulfides or 1,2-diphenyldiselane leading to the corresponding 4-chalcogen-substituted isoquinolines in moderate to good yields.
Ag-catalyzed cyclization of 2-alkynylbenzylazides offers a novel and efficient method for the synthesis of substituted isoquinoline. The reaction proceeds smoothly in moderate to good yields and tolerates considerable functional groups. The reaction conditions and the scope of the process are examined, and a plausible mechanism is proposed.