Pd-Catalyzed Isocyanide Assisted Reductive Cyclization of 1-(2-Hydroxyphenyl)-propargyl Alcohols for 2-Alkyl/Benzyl Benzofurans and Their Useful Oxidative Derivatization
摘要:
An unusual Pd-catalyzed isocyanide assisted 5exo-dig reductive cyclization of 1-(2-hydroxyphenyl)-propargyl alcohols is achieved for 2-alkyl/benzyl benzofurans. The reaction features a high substrate scope, insensitivity to air, and excellent product yielding. Further, a direct metal-free C-H functionalization (azidation, alkoxylation, and hydroxylation) and selective oxidative cleavage of thus synthesized 2-benzylfurans are described for azido-, alkoxy-, hydroxyl-, amide-, and tetrazolyl adducts.
accomplished the synthesis of 2-substituted benzofuran derivatives by the palladium-catalyzed reaction of 3-substituted propargylic carbonates with phenols. The 2-substituted benzofuran derivatives were obtained through the intermolecularcoupling of the 3-substituted propargylic carbonates with phenols, and sequential intramolecular cyclization reaction.
CuBr-Catalyzed Coupling of <i>N-</i>Tosylhydrazones and Terminal Alkynes: Synthesis of Benzofurans and Indoles
作者:Lei Zhou、Yi Shi、Qing Xiao、Yizhou Liu、Fei Ye、Yan Zhang、Jianbo Wang
DOI:10.1021/ol103009n
日期:2011.3.4
A new method for the synthesis of benzofurans or indoles via ligand-free CuBr-catalyzed coupling/cyclization of terminalalkynes with N-tosylhydrazones derived from o-hydroxy- or o-aminobenzaldehydes has been developed. A wide range of functional groups were found that are able to tolerate the reaction conditions.