Aryne and CO2-based formal [2 + 2 + 2] annulation to access tetrahydroisoquinoline-fused benzoxazinones

A three-component formal [2 + 2 + 2] annulation has been described from 3,4-dihydroisoquinolines, CO 2 , and benzynes, accessing tetrahydroisoquinoline-fused benzoxazinones in moderate to excellent yields.