Surfactant-Type Brønsted Acid Catalyzed Dehydrative Nucleophilic Substitutions of Alcohols in Water
作者:Seiji Shirakawa、Shū Kobayashi
DOI:10.1021/ol062813j
日期:2007.1.1
A protocol for the dehydrative nucleophilicsubstitution of benzyl alcohols with a variety of carbon- and heteroatom-centered nucleophiles using dodecylbenzenesulfonic acid (DBSA) as a surfactant-type Bronsted acid catalyst in water has been developed. The reaction system can be applied to the stereoselective C-glycosylation of 1-hydroxy sugars in water. [reaction: see text].
The Lewis Acidic Ruthenium-Complex-Catalyzed Addition of β-Diketones to Alcohols and Styrenes Is in Fact Brønsted Acid Catalyzed
作者:Pei Nian Liu、Zhong Yuan Zhou、Chak Po Lau
DOI:10.1002/chem.200700705
日期:2007.10.15
toward 1-phenylethanol in the presence of HClO4; it also fails to catalyze the addition of acetylacetone to 1-phenylethanol. On the basis of these observations, it is proposed and confirmed by independent experiments that the catalytic addition of beta-diketones to the secondary alcohols is in fact catalyzed by the Bronsted acid HClO4, which is generated by the reaction of cis-[Ru(6,6'-Cl2bipy)2(H2O)2](ClO4)2
Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2 (I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done by in situ 1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceed via η3-allyl complex formation or
报道了[Cp*Co(CH 3 CN) 3 ][SbF 6 ] 2 ( I )催化的二酮和β-酮酯与烯丙醇和苄醇的单烯丙基化和单烷基化。该方法不需要任何添加剂并提供区域选择性产物。通过原位1 H NMR 光谱以及对照实验进行了机理研究。已表明反应通过形成 η 3 -烯丙基络合物或烯丙基醚中间体进行。烷基化仅通过醚中间体发生。所得烯丙基化和烷基化产物已用于合成十一种新的三取代吡唑和一种吡唑啉酮。
An Efficient and General Iron-Catalyzed CC Bond Activation with 1,3-Dicarbonyl Units as a Leaving Groups
作者:Huanrong Li、Wenjuan Li、Weiping Liu、Zhiheng He、Zhiping Li
DOI:10.1002/anie.201006779
日期:2011.3.21
With our compliments: The 1,3‐dicarbonyl unit has been shown to be a new and useful leaving group for iron‐catalyzed bond cleavage (see scheme). This new strategy can complement the traditional Friedel–Crafts reaction and was applied in the synthesis of indene derivatives.
Copper-Catalyzed Oxidative Coupling of Benzylic C−H Bonds with 1,3-Dicarbonyl Compounds
作者:Nadine Borduas、David A. Powell
DOI:10.1021/jo801322p
日期:2008.10.3
A copper-catalyzedoxidativecoupling of benzylic C-H bonds with 1,3-dicarbonyl compounds is described. The reaction utilizes an inexpensive copper catalyst-oxidant system that is suitable for the coupling of a range of benzylic C-H bonds with various 1,3-dicarbonyl compounds. Kinetic isotope studies support a mechanism involving a benzylic hydrogen abstraction.