Arylimines generated in situ from aromatic aldehydes and anilines undergo smooth coupling with homophthalic anhydride in the presence of 10 mol% of molecular iodine under mild and neutral conditions to afford the corresponding cis-1-oxo-1,2,3,4-tetrahydroisoquinoline-4-carboxylic acids in excellent yields with high cis selectivity. The use of iodine makes this procedure simple, convenient, and cost-effective.
three-component reaction - iodine - isoquinolines - heterocycles - carboxylic acids
