Facile synthesis of isoquinolines by imination and subsequent palladacycle-catalyzed iminoannulation of internal alkynes

An efficient and facile synthesis of isoquinolines has been described via a tandem reaction of imination of o-halobenzaldehydes with tert-butyl amine and subsequent palladacycle-catalyzed iminoannulation of internal alkynes. This tandem reaction could be carried out successively in one pot without any special operation, and the annulation step could afford isoquinolines derivatives in moderate to good yields with high regioselectivity. In addition, the simple synthesis of indoles was realized by palladacycle-catalyzed annulation of o-iodoaniline or o-bromoanilines with internal alkynes.