Palladium-Catalyzed Mizoroki–Heck Reaction of Nitroarenes and Styrene Derivatives
作者:Toshimasa Okita、Kitty K. Asahara、Kei Muto、Junichiro Yamaguchi
DOI:10.1021/acs.orglett.0c00983
日期:2020.4.17
We have developed a Mizoroki–Heck reaction of nitroarenes with alkenes under palladium catalysis. The use of a Pd/BrettPhos catalyst promoted the alkenylation, whereas other catalysts led to a decrease in the product yield. In addition to nitroarenes, nitroheteroarenes were also applicable to the present reaction. The combination of a nucleophilic aromatic substitution (SNAr) with the denitrative alkenylation
A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, undermildconditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.
We have developed unprecedented methods for the direct transformation of primary alcohols to alkenes in the presence of hydrazine, and for the synthesis of mixed alkenes by the reaction of alcohols with hydrazones. The reactions are catalyzed by a manganese pincer complex and proceed in absence of added base or hydrogen acceptors, liberating dihydrogen, dinitrogen, and water as the only byproducts
Formation and Behavior of Fluorescent Lewis Acid−Base Exciplexes and Triplexes between 3-Aminostilbenes and Aliphatic Amines
作者:Frederick D. Lewis、Rajdeep S. Kalgutkar、Todd L. Kurth
DOI:10.1021/jp036723x
日期:2004.2.1
The excited singlet states of trans-3-aminostilbene and its N-methyl derivatives are strongly fluorescent in cyclohexane solution and have large singlet state dipole moments. Addition of low concen...
Catalytic semihydrogenation of internal alkynes using H2 is an attractive atom-economical route to various alkenes, and its stereocontrol has received widespread attention, both in homogeneous and heterogeneous catalyses. Herein, a novel strategy is introduced, whereby a poisoning catalytic thiol is employed as a reversible inhibitor of a ruthenium catalyst, resulting in a controllable H2-based semihydrogenation
使用H 2催化内炔烃半加氢是一种对各种烯烃具有吸引力的原子经济途径,其立体控制在均相和多相催化中都受到了广泛的关注。在此,引入了一种新策略,利用中毒催化硫醇作为钌催化剂的可逆抑制剂,导致内部炔烃的可控H 2半氢化。使用单一均相吖啶基钌钳形催化剂,在非常温和的条件下高效、高选择性地获得了 ( E )-和 ( Z )-烯烃。机理研究表明,( Z )-烯烃是生成( E )-烯烃的反应中间体,并且催化量的二齿硫醇的添加通过形成稳定的硫醇钌络合物来阻碍Z / E异构化步骤,同时仍然允许主要的氢化反应进行。因此,催化硫醇的存在或不存在控制了该炔烃半氢化的立体选择性,提供( E )-异构体作为最终产物或在( Z )-中间体处停止反应。所开发的系统也应用于末端烯烃的可控异构化,展示了如何通过简单的辅助添加剂对催化剂的可逆抑制来实现具有可切换选择性的金属催化。