Efficient total synthesis of dehydro-δ-viniferin through metal-halogen exchange cyclization

Bioactive dehydro-delta-viniferin was synthesized through an efficient and practical eight-step route, achieving an overall yield of 27%. The synthesis process involves an intramolecular cyclization and dehalogenation via a metal-halogen exchange, producing 3-arylbenzofuran, with the di-iodinated alpha-aryloxyketone serving as the key intermediate. Long reaction times and the use of excess reagent i-PrMgCl<middle dot>LiCl facilitate metal-halogen exchange cyclization and dehalogenation. This synthetic approach, scalable for the production of analogs, was successfully conducted for the first time in multigram quantities.