A Highly Active Catalyst for Pd-Catalyzed Amination Reactions: Cross-Coupling Reactions Using Aryl Mesylates and the Highly Selective Monoarylation of Primary Amines Using Aryl Chlorides
作者:Brett P. Fors、Donald A. Watson、Mark R. Biscoe、Stephen L. Buchwald
DOI:10.1021/ja8055358
日期:2008.10.15
reactivity for C-N cross-coupling reactions is reported. This catalyst system enables the use of arylmesylates as a coupling partner in C-N bond-forming reactions. Additionally, the use of BrettPhos permits the highly selective monoarylation of an array of primary aliphatic amines and anilines at low catalyst loadings and with fast reaction times, including the first monoarylation of methylamine. Lastly
Imidazolinium and amidinium salts as Lewis acid organocatalysts
作者:Oksana Sereda、Nicole Clemens、Tatjana Heckel、René Wilhelm
DOI:10.3762/bjoc.8.205
日期:——
The application of imidazolinium and amidiniumsalts as soft Lewis acid organocatalysts is described. These salts were suitable catalysts for the activation of unsaturated thioesters in a Diels-Alder reaction and in the ring opening of thiiranes and epoxides. The products were isolated in good yields. The mild catalysts did not cause desulfurization of the products containing a thiol or thiocarbonyl
Synergetic activation of CO<sub>2</sub> by the DBU-organocatalyst and amine substrates towards stable carbamate salts for synthesis of oxazolidinones
作者:Xiao-Chao Chen、Kai-Chun Zhao、Yin-Qing Yao、Yong Lu、Ye Liu
DOI:10.1039/d1cy01298c
日期:——
under mild conditions (80–100 °C, 12 h, 1.0 MPa CO2). Control experiments demonstrated that the formation of an ion-pair carbamate salt intermediate IS-B derived from the reaction of CO2, DBU (catalyst) and an amine (substrate) was the key step for this three-component reaction. The available DBU–amine–CO2 adduct intermediate (like IS-B-2) with fair stability will evolve into the thermodynamically stable
将CO 2转化为有价值的化学品的有效方法的开发引起了关于CO 2利用的挑战性问题的越来越多的关注。在此,DBU 有机超强碱催化CO 2、伯(脂肪族/芳香族)胺和 1,2-二氯乙烷(或其衍生物)制备恶唑烷酮的有效方法在温和条件下获得了 47-97% 的产率(80–100 °C, 12 h, 1.0 MPa CO 2 )。对照实验表明,由 CO 2反应生成的离子对氨基甲酸盐中间体IS-B、DBU(催化剂)和胺(底物)是这种三组分反应的关键步骤。可用的 DBU-胺-CO 2加合物中间体(如IS-B-2)在 1,2-二氯乙烷(或其衍生物)的攻击下,随着 DBU 的再生,将演变成热力学稳定的产物恶唑烷酮催化剂。或者,稳定性相对较差的 DBU-芳胺-CO 2加合物(如IS-B-1)的分解也可能导致 1,2-二氯乙烷(或其衍生物)与芳胺的竞争性取代反应。这项工作提供了对 DBU 催化剂和亲核胺底物协同 CO
A novel salt-free ruthenium-catalyzed alkylation of aryl amines
The alkylation of aryl aminesusing cyclic amines such as pyrrolidine proceeds via borrowing hydrogen methodology in the presence of 1 mol % Shvo catalyst. During the reaction multiple carbon–nitrogen cleavage and formation occurred. This novel reaction sequence leads to N-aryl-pyrrolidines and -piperidines.
Ligands for Transition-Metal-Catalyzed Cross-Couplings, and Methods of Use Thereof
申请人:Buchwald Stephen L.
公开号:US20090221820A1
公开(公告)日:2009-09-03
Ligands for transition metals are disclosed herein, which may be used in various transition-metal-catalyzed carbon-heteroatom and carbon-carbon bond-forming reactions. The disclosed methods provide improvements in many features of the transition-metal-catalyzed reactions, including the range of suitable substrates, number of catalyst turnovers, reaction conditions, and efficiency. For example, improvements have been realized in transition-metal-catalyzed cross-coupling reactions.