palladium-catalyzed benzylic-like nucleophilic substitution of benzofuran-2-ylmethyl acetate with N, S, O and C soft nucleophiles has been investigated. The success of the reaction is dramatically influenced by the choice of catalytic system: with nitrogen based nucleophiles the reaction works well with Pd2(dba)3/dppf, while with sulfur, oxygen and carbo-nucleophiles [Pd(η3-C3H5)Cl]2/XPhos is more efficient
Palladium-catalyzed intermolecular coupling of 2-haloallylic acetates with simple phenols, and sequential formation of benzofuran derivatives through the intramolecular cyclization
synthesis of 2-substituted benzofuran derivatives by the palladium-catalyzed reaction of 2-haloallylic acetates with simple phenols in the presence of a base. The reaction proceeded through the intermolecular attack of the nucleophile on the central carbon atom of the π-allyl group, carbon-halogen bond cleavage, and sequential intramolecularcyclization.
We investigated the intermolecular coupling reaction of 2-fluoroallylic acetates with simple phenols by the [Pd(C3H5)Cl]2, DPPF, and KHMDS at 100 °C for 16 h, and succeeded in obtaining 2-substituted benzofuran derivatives in good to high yield through the C–F bond activation and intermolecular cyclization.
我们研究了[Pd(C 3 H 5)Cl] 2,DPPF和KHMDS在100°C下16 h的2-氟烯丙基乙酸酯与简单酚的分子间偶联反应,并成功获得了2-取代的苯并呋喃衍生物。通过CF键活化和分子间环化,具有良好至高产的效果。
Palladium-catalyzed intermolecular coupling of 3-substituted propargylic carbonates with phenols: Synthesis of 2-substituted benzofuran derivatives
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.