tert-BuOK-mediated carbanion–yne intramolecular cyclization: synthesis of 2-substituted 3-benzylbenzofurans
摘要:
A mild, efficient, and regioselective carbanion-yne intramolecular cyclization mediated by t-BuOK for the synthesis of 2-substituted 3-benzylbenzofurans is developed. It was started from o-iodophenol (1), based on O-alkylation, and the Sonogashira reaction in sequence to produce 2-(2-phenylethynyl-phenoxy)-1-arylalkanones (5). An intramolecular carbanion-yne 5-exo-dig cyclization reaction of 5, which was mediated by t-BuOK, yielded title benzofurans in good yields. (C) 2011 Elsevier Ltd. All rights reserved.
Intermolecular Sonogashira Coupling and Intramolecular 5-<i>Exo</i>-<i>dig</i> Cycloisomerization Cascade: A One-Pot Pathway for Accessing (3-Benzylbenzofuran-2-yl)(phenyl)methanones
作者:Dakoju Ravi Kishore、Gedu Satyanarayana
DOI:10.1021/acs.joc.2c01101
日期:2022.8.5
straightforward strategy enabling access to 2,3-disubstitutedbenzo[b]furans. The whole synthetic process proceeds via a domino intermolecular Sonogashira coupling of 2-(2-bromophenoxy)-1-phenylethan-1-ones/alkyl 2-(2-bromophenoxy)acetates/2-(2-bromophenoxy)acetonitrile/1-(2-bromophenoxy)propan-2-one with terminal acetylenes followed by an intramolecular carbanion-yne cyclization in a 5-exo-dig manner and subsequent