A new palladium‐catalyzed intramolecular oxidativecycloisomerization of readily available starting materials, 2‐cinnamyl‐1,3‐dicarbonyls, has been demonstrated for the creation of structurally diverse 2‐benzyl furans. The cycloisomerization occurs by a regioselective 5‐exo‐trig pathway. The reaction shows a broad substrate scope with good to excellent yields. Furthermore, a one‐pot procedure has been
The Lewis Acidic Ruthenium-Complex-Catalyzed Addition of β-Diketones to Alcohols and Styrenes Is in Fact Brønsted Acid Catalyzed
作者:Pei Nian Liu、Zhong Yuan Zhou、Chak Po Lau
DOI:10.1002/chem.200700705
日期:2007.10.15
toward 1-phenylethanol in the presence of HClO4; it also fails to catalyze the addition of acetylacetone to 1-phenylethanol. On the basis of these observations, it is proposed and confirmed by independent experiments that the catalytic addition of beta-diketones to the secondary alcohols is in fact catalyzed by the Bronsted acid HClO4, which is generated by the reaction of cis-[Ru(6,6'-Cl2bipy)2(H2O)2](ClO4)2
Perchloric Acid Catalyzed Homogeneous and Heterogeneous Addition of β-Dicarbonyl Compounds to Alcohols and Alkenes and Investigation of the Mechanism
作者:Pei Nian Liu、Li Dang、Qing Wei Wang、Shu Lei Zhao、Fei Xia、Yu Jie Ren、Xue Qing Gong、Jun Qin Chen
DOI:10.1021/jo100517k
日期:2010.8.6
The direct addition of various β-dicarbonylcompounds to a series of secondary alcohols and alkenes has been achieved using 1 mol % perchloric acid (HClO4) as the catalyst. The HClO4-catalyzed reactions could be conveniently conducted in commercial solvent and gave moderate to excellent yields. Moreover, the silica gel-supported HClO4 could also catalyze the heterogeneous addition for a series of substrates
transition-metal-catalyzed carbon-carbon coupling of a wide range of benzylic/allylicalcohols with β-diones, β-keto esters, and dialkyl malonates is reported. In a representative screening of transition-metal catalysts, salts of Zn, Cu, Fe, Sc, Ru, Pt, Ta, and Mo were found to furnish the coupling products. In light of the results obtained, among all of these catalysts copper(II) triflate was found to be relatively
报道了一种快速且高效的合成微波辐照方案,用于过渡金属催化的各种苄醇/烯丙醇与 β-二酮、β-酮酯和丙二酸二烷基酯的碳-碳偶联。在对过渡金属催化剂的代表性筛选中,发现 Zn、Cu、Fe、Sc、Ru、Pt、Ta 和 Mo 的盐可以提供偶联产物。鉴于所获得的结果,在所有这些催化剂中,发现与其他催化剂相比,三氟甲磺酸铜 (II) 相对更有效,即使在反应性较低的苯甲醇或二酯的情况下也是如此。有趣的是,这些 MW 辐照反应是在或多或少 MW 透明的介质中进行的,例如甲苯,具有非常低的 tanδ,或在纯净条件下进行。
Selective Benzylic and Allylic Alkylation of Protic Nucleophiles with Sulfonamides through Double Lewis Acid Catalyzed Cleavage of sp<sup>3</sup>Carbon-Nitrogen Bonds
broad range of tosyl‐activated benzylic and allylic amines to give diversely functionalized products in good to excellent yields and with high regioselectivity. Furthermore, the cross‐coupling reaction of 1,3‐dicarbonyl compounds with benzylic propargylicamine derivatives has been successfully applied to the one‐step synthesis of polysubstituted furans and benzofurans.