开发了一种碱促进的有机铵盐直接脱氨基烯化。仅由 KO t Bu 介导,一系列苄基和肉桂基铵盐与砜类顺利反应,以良好至高收率生产有价值的二苯乙烯和相关的 1,3-二烯衍生物,具有良好的官能团耐受性和优异的E选择性。利用该方法,还成功制备了具有生物活性的白藜芦醇和DMU-212,进一步证明了该反应的实用性。
两个亲电子试剂之间的交叉亲电子试剂偶联是在化学计量外部还原剂存在下生成 CC 键的有效且经济的方法。在此,我们报告了一种通过可见光光氧化还原催化实现第一个无外部还原剂的交叉亲电子偶联的新策略。各种带有伯、仲和叔 CN 键的四烷基铵盐与醛/酮和 CO2 进行选择性偶联。值得注意的是,原位生成的副产物三甲胺被有效地用作电子供体。此外,该协议表现出温和的反应条件、低催化剂负载、广泛的底物范围、良好的官能团耐受性和容易的可扩展性。机理研究表明,苄基自由基和阴离子可能是通过光催化产生的关键中间体,
Iridium-Catalyzed Allylic Substitutions with Cyclometalated Phosphoramidite Complexes Bearing a Dibenzocyclooctatetraene Ligand: Preparation of (π-Allyl)Ir Complexes and Computational and NMR Spectroscopic Studies
作者:Jevgenij A. Raskatov、Mascha Jäkel、Bernd F. Straub、Frank Rominger、Günter Helmchen
DOI:10.1002/chem.201201772
日期:2012.11.5
(π‐Allyl)Ircomplexes derived from dibenzocyclooctatetraene and phosphoramidites by cyclometalation are effective catalysts for allylicsubstitution reactions of linear monosubstituted allylic carbonates. These catalysts provide exceptionally high degrees of regioselectivity and allow the reactions to be run under aerobic conditions. A series of (π‐allyl)Ircomplexes were prepared and characterized
A palladium-catalyzed difunctionalization of bicyclicalkenes with organoammonium salts and organoboronic compounds was reported. A wide range of functionalized cyclic products, including those bearing functional groups, were produced stereoselectively in good to excellent yields. The gram-scale experiment, one-pot operation, and synthetic application of β-borylated products further demonstrated the