Phosphazene Superbase-Mediated Regio- and Stereoselective Iodoaminocyclization of 2‑(1-Alkynyl)benzamides for the Synthesis of Isoindolin-1-ones

Phosphazene superbase
P4-t-Bu mediated
iodoaminocyclization of 2-(1-alkynyl)­benzamides is reported. The reaction
works under ambient conditions and instantaneously results in the
synthesis of isoindolin-1-ones in 65–97% yields, in a regio-
and stereoselective manner. The exclusive formation of products with Z-geometry (across the exo CC bond) has been confirmed
through X-ray crystallography. The methodology also provides an easy
access to aristolactams, an important class of natural products. This
has been successfully demonstrated by synthesizing two aristolactam
derivatives (including Cepharanone B).