A facile and stereoselective synthesis of dienediones and 6-oxo-2,4-dienoic esters
摘要:
Ostopanic acid and ethyl 6-oxodocosa-2,4-dienoate were synthesized by a short route based on the palladium catalyzed isomerization of ynone and ynoic ester, respectively, using pent-4-ynal as a starting material.
Silver-Free Activation of Ligated Gold(I) Chlorides: The Use of [Me<sub>3</sub>NB<sub>12</sub>Cl<sub>11</sub>]<sup>−</sup>as a Weakly Coordinating Anion in Homogeneous Gold Catalysis
作者:Michael Wegener、Florian Huber、Christoph Bolli、Carsten Jenne、Stefan F. Kirsch
DOI:10.1002/chem.201404487
日期:2015.1.12
Phosphane and N‐heterocycliccarbene ligated gold(I) chlorides can be effectively activated by Na[Me3NB12Cl11] (1) under silver‐free conditions. This activation method with a weakly coordinating closo‐dodecaborate anion was shown to be suitable for a large variety of reactions known to be catalyzed by homogeneous gold species, ranging from carbocyclizations to heterocyclizations. Additionally, the
在无银条件下,Na [Me 3 NB 12 Cl 11 ](1)可以有效活化磷化氢和N-杂环卡宾相连的氯化金(I)。这种具有弱配位的活化方法闭合碳-dodecaborate阴离子被证明是适合于大量的各种已知由均匀的金物种催化的反应,从carbocyclizations到heterocyclizations的。此外,还证明了1在以前未知的5-甲硅烷氧基-1,6-炔烃转化中的能力。
Cycloisomerization of Aromatic Homo- and Bis-homopropargylic Alcohols via Catalytic Ru Vinylidenes: Formation of Benzofurans and Isochromenes
作者:Alejandro Varela-Fernández、Carlos González-Rodríguez、Jesús A. Varela、Luis Castedo、Carlos Saá
DOI:10.1021/ol902212h
日期:2009.11.19
Ru-catalyzed cycloisomerizations of aromatic homo- and bis-homopropargylic alcohols effectively afford benzofurans and isochromenes. These processes proved to be chemo- and regioselective (5-, and 6-endo cyclizations) derived from key Ru vinylidene intermediates. The presence of an amine/ammonium base−acid pair is crucial for the catalytic cycle.
Gold-Catalyzed Tandem Cycloisomerization-Halogenation of Chiral Homopropargyl Sulfonamides
作者:Chao Shu、Long Li、Cang-Hai Shen、Peng-Peng Ruan、Chao-Yue Liu、Long-Wu Ye
DOI:10.1002/chem.201503891
日期:2016.2.12
Two new gold‐catalyzed tandem cycloisomerization–halogenation reactions of chiralhomopropargylsulfonamides have been developed. Various enantioenriched 3,3‐diiodopyrrolidin‐2‐ols and 3‐fluoropyrrolidin‐2‐ols were obtained in moderate‐to‐good yields with excellent enantio‐ and diastereoselectivity.
Gold-catalyzed efficient synthesis of azepan-4-ones via a two-step [5 + 2] annulation
作者:Li Cui、Longwu Ye、Liming Zhang
DOI:10.1039/c001314e
日期:——
A surprisingly efficient synthesis of azepan-4-ones via a two-step [5â+â2] annulation is developed. This reaction involves a key gold catalysis and shows generally high regioselectivities and good to excellent diastereoselectivities.