Chiral ligand-controlled asymmetric conjugate amination of enoates with lithium mesitylmethyl(trimethylsilyl)amide
摘要:
Lithium mesitylmethyl(trimethylsilyl)amide behaved as a nice amination agent in a chiral ligand-controlled conjugate addition reaction of tert-butyl cinnamate to give the conjugate amination product with 99% ee in 90% yield. Other acyclic and cyclic enoates were also aminated in reasonably high enantioselectivity, while the deprotonation of abstractable proton of enoates caused yield loss of the conjugate amination products, due to the bulkiness and enriched basicity of the lithium amide. Although such steric bulkiness made hard the hydrogenolytic cleavage of a mesitylmethyl-N bond of the adducts, a new protocol comprising N-chlorination-regioselective dehydro-chlorination-transoximation was developed for N-dearylmethylation, giving 3-aminoalkanoates in reasonably good yields. (c) 2006 Elsevier Ltd. All rights reserved.
The bis-1,4-dimesityl-1,2,3-triazol-5-ylidene–palladium complex (1a) successfully catalyzes the Mizoroki–Heck and Sonogashira coupling reactions with aryl bromides to give the corresponding alkenes and alkynes, respectively, in good to excellent yields. In the Mizoroki–Heck reaction, electron-rich, electron-poor, and functionalized aryl bromides and alkenes are tolerated, while the substrates are limited
Selective Construction of C−C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
作者:Xin Liu、Thomas Werner
DOI:10.1002/adsc.202001209
日期:2021.2.16
manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon‐carbon single (C−C) and carbon‐carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C−C vs. C=C bonds can be controlled by the
Palladium‐Based Catalysts Supported by Unsymmetrical XYC
<sup>–1</sup>
Type Pincer Ligands: C5 Arylation of Imidazoles and Synthesis of Octinoxate Utilizing the Mizoroki–Heck Reaction
作者:Ankur Maji、Ovender Singh、Sain Singh、Aurobinda Mohanty、Pradip K. Maji、Kaushik Ghosh
DOI:10.1002/ejic.202000211
日期:2020.5.10
methyl)phenyl)morpholine H = dissociableproton). Molecular structure of catalysts (C1–C4) were further established by single X‐ray crystallographic studies. The catalytic performance of palladacycles (C1–C4) was explored with the direct Csp2–H arylation of imidazoles with aryl halide derivatives. These palladacycles were also applied for investigating of Mizoroki–Heck reactions with aryl halides and acrylate
使用简单的锚定配体L 1-4 H(L 1 H = 2-(((2-(4-‐甲氧基亚苄基)-1-1-苯基肼基)),设计并合成了一系列新的不对称(XYC –1型)Palladacycles(C1 – C4))甲基)吡啶,L 2 H = N,N-二甲基-4-((2-苯基-2-(吡啶-2-基甲基)肼基)甲基)苯胺,L 3 H = N,N-二乙基-4- ((2-苯基-2-(吡啶-2-基甲基)肼基)甲基)苯胺和L 4 H = 4-(4-((2-苯基-2-(吡啶-2-基甲基)肼基)甲基)苯基吗啉H =游离质子)。催化剂的分子结构(C1 - C4)通过单X射线晶体学研究进一步确定。通过咪唑与芳基卤化物衍生物的直接Csp 2 -H芳基化研究了palladacycles(C1 - C4)的催化性能。这些palladacycles还用于研究与芳基卤化物和丙烯酸酯衍生物的Mizoroki-Heck反应。在催化循环过
An efficient palladium catalyzed Mizoroki–Heck cross-coupling in water
作者:Sanjay N. Jadhav、Chandrashekhar V. Rode
DOI:10.1039/c7gc02869e
日期:——
Pd-catalysed Mizoroki–Heck coupling reaction was successfully performed in water in the absence of any additives under aerobic conditions. The various key reaction parameters that affect the yield of the desired cross-coupling product were optimized. The Pd(PPh3)4/Et3N/H2O/98 °C catalyst system was found to be highly active (TOF = 12 to 14 h−1) towards achieving excellent yield of the Mizoroki–Heck coupling
在有氧条件下,在没有任何添加剂的情况下,水中成功地进行了均相Pd催化的Mizoroki-Heck偶联反应。优化了影响所需交叉偶联产物收率的各种关键反应参数。发现Pd(PPh 3)4 / Et 3 N / H 2 O / 98°C催化剂体系具有很高的活性(TOF = 12至14 h -1),可实现出色的Mizoroki–Heck偶联产物的收率。在最短的反应时间内,吸电子以及给电子的芳基溴化物和氯化物种类繁多。钯(PPh 3)4对Mizoroki-Heck偶联反应过程中的催化剂失活进行了研究,并发展了实现十倍Pd-金属可循环性而又没有明显损失其活性的策略。因此,提出的机制提供了在水性介质中接触各种烯烃的途径,从而使该协议变得环保。
Efficient Mizoroki–Heck coupling reactions using phosphine-modified Pd(II)–picolinate complex
作者:Sonam Sharma、Bibhas R. Sarkar
DOI:10.1080/00397911.2018.1428347
日期:2018.4.18
ABSTRACT Efficient Mizoroki–Heck couplings were obtained using a very easily synthesizable palladium(II) complex of hemilabile N–O ligand (picolinate), with high turnover frequencies up to >10,000 h−1, in just 15 min, with high selectivity of >99% to the desired products. Wide applicability of the simple-looking palladium complex catalyst was established with differently functionalized substrates.