Nitrogenated Azaphilone Derivatives through a Silver-Catalysed Reaction of Imines from ortho-Alkynylbenzaldehydes

Nitrogenated azaphilones are interesting natural products with a wide range of applications. The structure of these compounds is characterized by the presence of an isoquinolinone framework. Here, we describe a new multicomponent silver-catalysed reaction that allows the transformation of simple imines derived from ortho-alkynylbenzaldehydes into complex nitrogenated azaphilonetype molecules in a straightforward way. This atom-economical process is high yielding, technically very simple and proceeds through a series of cascade processes that imply cycloisomerisation and formal cross-coupling reactions. This conceptually new process formally involves the synchronised catalytic generation and selective coupling of a nucleophile (isoquinolinone) and an electrophile (isoquinolinium). Some interesting colour properties of the synthesized azaphilone-type molecules are discussed.