Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor
作者:Steven P. Cummings、Thanh-Ngoc Le、Gilberto E. Fernandez、Lorenzo G. Quiambao、Benjamin J. Stokes
DOI:10.1021/jacs.6b02132
日期:2016.5.18
There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric
使用水作为化学计量的 H 或 D 原子供体的简单烯烃和炔烃的催化转移氢化的例子很少。我们发现二硼试剂使用钯催化剂有效地介导了 H 或 D 原子从水中直接转移到不饱和 CC 键上。该反应在环境温度下对多种烯烃和炔烃进行,硼酸是唯一的副产物。机理实验表明,该反应是通过从水中的氢原子转移生成 Pd 氢化物中间体而实现的。重要的是,还实现了从化学计量的 D2O 中完全掺入氘。
Iron‐Catalyzed Wacker‐type Oxidation of Olefins at Room Temperature with 1,3‐Diketones or Neocuproine as Ligands**
Herein, we describe a convenient and general method for the oxidation of olefins to ketones using either tris(dibenzoylmethanato)iron(III) [Fe(dbm)3] or a combination of iron(II) chloride and neocuproine (2,9-dimethyl-1,10-phenanthroline) as catalysts and phenylsilane (PhSiH3) as additive. All reactions proceed efficiently at room temperature using air as sole oxidant. This transformation has been
Oxidative Cleavage of Silyl Ethers by an Oxoammonium Salt
作者:Nicholas Leadbeater、Jacob Loman、Vincent Pistritto、Christopher Kelly
DOI:10.1055/s-0035-1561498
日期:——
A method for the oxidativecleavage of silyl ethers to their corresponding carbonyl species mediated by an oxoammonium salt is described. The resulting aldehydes and ketones are obtained under mild reaction conditions with no observed overoxidation. For robust substrates, heating to reflux temperatures significantly reduces the reaction time.
specific chemoselectivity for hydrogenation that has never been achieved by other palladium‐catalyzed methods. Either aliphatic or aromatic N‐Cbz groups could be deprotected to the corresponding free‐amines, while the hydrogenolysis of benzyl esters and ethers did not proceed. Furthermore, aryl chlorides and epoxides were tolerant under the Pd/ceramic‐catalyzed hydrogenation conditions. 5 % Pd/ceramic
Difluorocarbene Addition to Alkenes and Alkynes in Continuous Flow
作者:Pauline Rullière、Patrick Cyr、André B. Charette
DOI:10.1021/acs.orglett.6b00573
日期:2016.5.6
The first in-flow difluorocarbene generation and addition to alkenes and alkynes is reported. The application of continuousflow technology allowed for the controlled generation of difluorocarbene from TMSCF3 and a catalytic quantity of NaI. The in situ generated electrophilic carbene reacts smoothly with a broad range of alkenes and alkynes, allowing the synthesis of the corresponding difluorocyclopropanes