英文关于苯并呋喃.pdf

Synthesis of 2,3-Disubstituted Benzo[b]furans by the Palladium-Catalyzed Coupling of o-Iodoanisoles and Terminal Alkynes, Followed by Electrophilic Cyclization Dawei Yue, Tuanli Yao, and Richard C. Larock* Department of Chemistry, Iowa State University, Ames, Iowa 50011 larock@ Received June 24, 2005 2,3-Disubstituted benzo[b]furans are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of various o-iodoanisoles and terminal alkynes, followed by electrophilic cyclization with I , PhSeCl, orp -O NC H SCl. Aryl- and vinylic-substituted alkynes 2 2 6 4 undergo electrophilic cyclization in excellent yields. Biologically important furopyridines can be prepared by this approach in high yields. Introduction important calcium blockers13 and phytoestrogens.14 For The benzo[b]furan nucleus is prevalent in a wide instance, XH-1415 was the first reported potent non- variety of biologically active natural and unnatural nucleoside adenosine A1 agonist16 and obovaten is known compounds.1 Many 2-arylbenzofuran derivatives are well- as an active antitumor agent.17 known to exhibit a broad range of biological activities, including anticancer,2 antiproliferative,3 antiviral,4 an- tifungal,5 immunosuppressive,6 antiplatelet,7 antioxida- tive,8 insecticidal,9 antiinflammatory,10 antifeedant,11 and