Cross-coupling reaction of organosilicon nucleophiles
申请人:——
公开号:US20020183516A1
公开(公告)日:2002-12-05
Improved methods for generating a —C—C— bond by cross-coupling of a transferable group with an acceptor group. The transferable group is a substituent of an organosilicon nucleophile and the acceptor group is provided as an organic electrophile. The reaction is catalyzed by a Group 10 transition metal complex (e.g., Ni, Pt or Pd), particularly by a palladium complex. Certain methods of this invention use improved organosilicon nucleophiles which are readily prepared, can give high product yields and exhibit high stereo selectivity. Methods of this invention employ activating ions such as halides, hydroxide, hydride and silyloxides. In specific embodiments, organosilicon nucleophilic reagents of this invention include siloxanes, particularly cyclic siloxanes. The combination of the cross-coupling reactions of this invention with ring-closing metathesis, hydrosilylation and intramolecular hydrosilylation reactions provide useful synthetic strategies that have wide application.
Stereospecific Palladium-Catalyzed Cross-Coupling of (<i>E</i>)- and (<i>Z</i>)-Alkenylsilanolates with Aryl Chlorides
作者:Scott E. Denmark、Jeffrey M. Kallemeyn
DOI:10.1021/ja065988x
日期:2006.12.1
geometrically defined (E)- and (Z)-alkenyl- and styrylsilanolates with a wide variety of aromatic and heteroaromatic chlorides has been achieved. Under catalysis by bulky, biphenyl-derived phosphines and allylpalladium chloride, the (preformed, stable) potassium salts of di-, tri- and tetrasubstituted alkenyldimethylsilanols undergo high yielding and highly stereospecific coupling to aryl chlorides in THF or dioxane
alternatives to Wittig chem-istry are needed to construct olefins from carbonyl compounds, but none have been developed to-date. Here we report an atom-economical olefination of carbonyls via aldol-decarbonylative coupling of aldehydes using robust and recyclable supported Pd catalysts, producing only CO and H2O as waste. The reaction affords homocoupling of aliphatic al-dehydes, as well as heterocoupling
需要新的原子经济替代 Wittig 化学来从羰基化合物构建烯烃,但迄今为止还没有开发出来。在这里,我们报告了使用坚固且可回收的负载型 Pd 催化剂通过醛的醛醇-脱羰基偶联实现羰基的原子经济烯化,仅产生 CO 和 H2O 作为废物。该反应提供了脂肪族醛的同偶联,以及脂肪族和芳香族醛的杂偶联。计算可以深入了解反应的选择性和热力学。串联羟醛脱羰反应为探索新的羰基反应以构建烯烃打开了大门。
Synthesis of 4-Nitrophenyl Sulfones and Application in the Modified Julia Olefination
作者:Jieping Zhu、Daniela Mirk、Jean-Marie Grassot
DOI:10.1055/s-2006-939682
日期:——
4-Nitrophenyl (NP) sulfones were successfully employed in the modifiedJuliaolefination reaction with carbonyl compds. The olefination reaction proceeds through a sequence of aldol addn., Smiles rearrangement, and elimination. The sulfones are easily prepd. in high yields in a two-step sequence starting from inexpensive com. available para-fluoronitrobenzenes via nucleophilic arom. substitution by
4-硝基苯基 (NP) 砜成功地用于与羰基化合物的改性 Julia 烯化反应。烯化反应通过羟醛加成、Smiles 重排和消除的顺序进行。砜很容易制备。从廉价的 com 开始,以两步顺序高产。可通过亲核芳族获得对氟硝基苯。被硫醇取代,随后被氧化。在标准下。使适应。NP 砜与多种芳烃之间的改良 Julia 反应。醛提供相应的苯乙烯、芪和肉桂酸酯衍生物。产率 ?97% 和良好的立体选择性。提出了机械原理来解释 obsd。结果。[在 SciFinder (R) 上]
Cross-coupling reactions of alkenylsilanols with fluoroalkylsulfonates: development and optimization of a mild and stereospecific coupling process
作者:Scott E. Denmark、Christopher S. Regens
DOI:10.1016/j.tetlet.2010.11.133
日期:2011.4
The development of an effective protocol for the palladium-catalyzed cross-coupling of (E)-alkenylsilanols with aryl triflates is described. A critical component in the optimization of this method was balancing the stability and reactivity of the triflates in the presence of a nucleophilic promoter. This report highlights the use of a slightly soluble Brønsted base promoter that allows for a low, steady-state
描述了钯催化 ( E )-烯基硅烷醇与芳基三氟甲磺酸酯交叉偶联的有效方案的开发。优化该方法的一个关键组成部分是在亲核启动子的存在下平衡三氟甲磺酸酯的稳定性和反应性。本报告重点介绍了使用微溶的 Brønsted 碱促进剂,它允许溶液中烯基(二甲基)硅烷醇化物的低、稳态浓度,从而促进交叉偶联,而不是三氟甲磺酸酯的 S-O 键断裂。