An Expedient Synthesis of Bis-Fused Benzofuran and a Two-Directional Ring-Closing Metathesis for the Synthesis of Bisbenzoxepines and Bisbenzoxocines

摘要

Synthesis of bis-fused benzofuran derivatives by the implementation of palladium-mediated intramolecular cyclization is described. To our knowledge, this is the first report of the synthesis of bis-fused benzofuran by this protocol. Bisbenzoxepine and bis-benzoxocine derivatives were also synthesized by the application of two-directional ring-closing metathesis.As a part of our continuing study concerning the carbon-carbon bond-forming reactions utilizing the palladium-mediated intramolecular cyclization strategy, we have reported variously functionalized medium-sized hetero-cycles with a possible evaluation of the potentially bioac-tive moieties. We have also developed an important synthetic methodology for the construction of medium-sized heterocyclic compounds from the unactivated allyl-ic system via the C-H activation method by the application of intramolecular Heck reaction sequence.