CuI Mediated One-Pot Cycloacetalization/Ketalization of <i>o</i>‑Carbonyl Allylbenzenes: Synthesis of Benzo­bicyclo­[3.2.1]­octane Core

CuI/DMSO-mediated intramolecular cyclo­acetalization/ketalization of o-carbonyl allylbenzenes has been achieved for constructing [6,6,5]-tricycles having a ketal motif in good yields. The expeditious one-step route provides a three C–O bond formation. The key products with the structural framework of a benzofused dioxa­bicyclo­[3.2.1]­octane core have been confirmed by X-ray crystallographic analysis. Synthesis of dihydro­isocoumarin has been studied.