Cyclic (Alkyl)(amino)carbene Ligands Enable Cu‐Catalyzed Markovnikov Protoboration and Protosilylation of Terminal Alkynes: A Versatile Portal to Functionalized Alkenes**
作者:Yang Gao、Sima Yazdani、Aaron Kendrick、Glen P. Junor、Taeho Kang、Douglas B. Grotjahn、Guy Bertrand、Rodolphe Jazzar、Keary M. Engle
DOI:10.1002/anie.202106107
日期:2021.9
donating cyclic (alkyl)(amino)carbene (CAAC) ligands. Using this method, both alkyl- and aryl-substituted alkynes are coupled with a variety of boryl and silyl reagents with high α-selectivity. The reaction is scalable, and the products are versatile intermediates that can participate in various downstream transformations. Preliminary mechanistic experiments shed light on the role of CAAC ligands in this
Highly Selective Methods for Synthesis of Internal (α-) Vinylboronates through Efficient NHC–Cu-Catalyzed Hydroboration of Terminal Alkynes. Utility in Chemical Synthesis and Mechanistic Basis for Selectivity
作者:Hwanjong Jang、Adil R. Zhugralin、Yunmi Lee、Amir H. Hoveyda
DOI:10.1021/ja2007643
日期:2011.5.25
procedures (1 mol % catalyst loading). Mechanistic studies are presented, indicating that α selectivity arises from the structural and electronic attributes of the NHC ligands and the alkyne substrates. Consistent with suggested hypotheses, catalyticreactions with a Cu complex, derived from an N-adamantyl-substituted imidazolinium salt, afford high β selectivity with the same class of substrates and under
Automated library synthesis of cyclopropyl boronic esters employing diazomethane in a tube-in-tube flow reactor
作者:Hannes F. Koolman、Stanislaw Kantor、Andrew R. Bogdan、Ying Wang、Jeffrey Y. Pan、Stevan W. Djuric
DOI:10.1039/c6ob00715e
日期:——
The efficient synthesis of cyclopropyl boronic esters in library format using a diazomethane flow reactor has been achieved. A pivotal component of the system is a fully automated tube-in-tube reactor allowing for safe handling of hazardous diazomethane on repeated small scale and for the generation of larger quantities of product. The setup enables the repeated execution of Pd-catalyzed cyclopropanation
diffraction. Subsequently, the catalytic activity of as a pre-catalyst for the hydroboration of alkynes and nitriles was investigated. It exhibited good functional group tolerance towards both terminal alkynes and nitriles under solvent-free and low-load conditions. The potential mechanism for the -catalyzed reaction of alkynes and nitriles with HBpin are proposed by the NMR spectroscopy of the intermediates
以水杨醛衍生物和2-氨基吡啶为原料合成了双核希夫碱铝配合物(,)。配合物 和 通过 NMR 和单晶 X 射线衍射进行了表征。随后,研究了其作为炔烃和腈的硼氢化反应预催化剂的催化活性。在无溶剂和低负载条件下,它对末端炔烃和腈表现出良好的官能团耐受性。通过中间体的核磁共振谱提出了炔烃和腈与 HBpin 催化反应的潜在机理。