Copper-NHC-Mediated Semihydrogenation and Hydroboration of Alkynes: Enhanced Catalytic Activity Using Ring-Expanded Carbenes
作者:Jonathan W. Hall、Darcy M. L. Unson、Paul Brunel、Lee R. Collins、Mateusz K. Cybulski、Mary F. Mahon、Michael K. Whittlesey
DOI:10.1021/acs.organomet.8b00467
日期:2018.9.24
tert-butoxide complexes bearing five-, six-, and seven-membered ring N-heterocycliccarbenes, prepared by protonolysis of (NHC)CuMes with tBuOH, have been used as catalytic precursors in the semihydrogenation of alkynes with silanes/tBuOH and the hydroboration of alkynes with HBPin. Both processes proceed with high regioselectivity and show enhancements with six- and seven-membered ring carbenes.
由(NHC)CuMes与t BuOH质子分解制得的一系列带有五元,六元和七元环N-杂环卡宾的二配位叔丁醇铜配合物已被用作苯甲酸半加氢反应的催化前体。炔烃与硅烷/ t BuOH的混合,以及炔烃与HBPin的硼氢化。两种方法都具有较高的区域选择性,并显示六元和七元环卡宾具有增强作用。
Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights <i>Via</i> Experimental and Computational Studies
作者:Nhan N. H. Ton、Binh Khanh Mai、Thanh Vinh Nguyen
DOI:10.1021/acs.joc.1c01208
日期:2021.7.2
hydroboration reaction of alkynes. A broad range of vinylboranes can be easily accessed via this metal-free protocol. Similar hydroboration reactions of alkenes and epoxides can also be efficiently catalyzed by the same tropylium catalysts. Experimentalstudies and DFT calculations suggested that the reaction follows an uncommon mechanistic pathway, which is triggered by the hydride abstraction of pinacolborane
Aluminum-Catalyzed Selective Hydroboration of Alkenes and Alkynylsilanes
作者:Feng Li、Xu Bai、Yuan Cai、Han Li、Shuo-Qing Zhang、Feng-Hua Liu、Xin Hong、Youjun Xu、Shi-Liang Shi
DOI:10.1021/acs.oprd.9b00205
日期:2019.8.16
An efficient aluminum-catalyzed selective hydroboration of alkenes and alkynylsilanes is reported. A wide variety of alkenes and alkynylsilanes bearing various functional groups and heterocyclic substituents were converted to boronicester products in good yields with high selectivity. Mechanistically, density functional theory calculations favored a mechanism involving the insertion of the double
Zinc‐Catalysed Hydroboration of Terminal and Internal Alkynes
作者:Souvik Mandal、Sayantan Mandal、K. Geetharani
DOI:10.1002/asia.201900839
日期:2019.12.13
A regioselective hydroboration of alkynes has been developed by using commercially available zinc triflate as a catalyst, in the presence of catalytic amount of NaBHEt3 . The reaction tolerates a wide range of terminalalkynes having several synthetically useful functional groups and proceeds regioselectively to furnish hydroborated products in moderate to excellent yields. This system shows moderate
Anionic O → α- and β-Vinyl Carbamoyl Translocation of 2-(<i>O</i>-Carbamoyl) Stilbenes
作者:Mark A. Reed、Michelle T. Chang、Victor Snieckus
DOI:10.1021/ol049740t
日期:2004.7.1
[reaction: see text] New anionic oxygen to alpha- and beta-vinyl carbamoyl migration reactions, 17a and 26a-c --> 18 and 30a-c, proceed under LDA-mediated conditions leading stereoselectively to highly substituted stilbenes bearing electron-donating and -withdrawing substituents. Compounds 17a and 26a-c are prepared by combination of efficient, directedorthometalation, Sonogashira, and Suzuki-Miyaura