使用三(五氟苯基)硼烷(B(C 6 F 5)3)作为催化引发剂,开发了炔烃和苯乙烯与HBpin的硼氢化反应。提出氢硼化是通过(B(C 6 F 5)3)的路易斯酸对炔烃的路易斯酸活化作用而引发的,以形成高反应性的两性离子物质,该物质随后与HBpin反应生成烯基硼酸酯。该两性离子还显示出可能成为苯乙烯加氢硼化的有效催化剂。两性离子中间体类似于在Piers硼烷催化的硼氢化反应和B(C 6 F 5)3炔烃的1,1碳硼化反应中提出的中间体。
NiH‐Catalyzed Migratory Defluorinative Olefin Cross‐Coupling: Trifluoromethyl‐Substituted Alkenes as Acceptor Olefins to Form
<i>gem</i>
‐Difluoroalkenes
a NiH-catalyzed migratory defluorinative coupling between two electronically differentiated olefins. A broad range of unactivated donor olefins can be joined directly to acceptor olefins containing an electron-deficient trifluoromethyl substituent in both intra- and intermolecular fashion to form gem-difluoroalkenes. This migratory coupling shows both site- and chemoselectivity under mild conditions
Methylenespiro[2.3]hexanes via Nickel-Catalyzed Cyclopropanations with [1.1.1]Propellane
作者:Songjie Yu、Adam Noble、Robin B. Bedford、Varinder K. Aggarwal
DOI:10.1021/jacs.9b10689
日期:2019.12.26
with poor selectivity. Herein, we report that nickel(0) catalysis enables the use of [1.1.1]propellane as a carbene precursor in cyclopropanations of a range of functionalized alkenes to give methylenespiro[2.3]hexane products. Computational studies provide support for initial formation of a Ni(0)-[1.1.1]propellane complex followed by concerted double C-C bond activation to give the key 3-methylenecyclobutylidene-nickel
aluminum-catalyzed hydroboration of a variety of nitriles and alkynes. Moreover, aluminum-catalyzed hydroboration is expanded to more challenging substrates such as alkene, pyridine, imine, carbodiimide, and isocyanides. More importantly, we have shown that the aluminum dihydride catalyzed both intra- and intermolecular chemoselective hydroboration of nitriles and alkynes over other reducible functionalities for
[EN] SUBSTITUTED INDOLE COMPOUNDS USEFUL AS TLR INHIBITORS<br/>[FR] COMPOSÉS D'INDOLE SUBSTITUÉS UTILES EN TANT QU'INHIBITEURS DE TLR
申请人:BRISTOL MYERS SQUIBB CO
公开号:WO2019126113A1
公开(公告)日:2019-06-27
Disclosed are compounds of Formula (I) N-oxides, or salts thereof, wherein G, A, R1, R5, and n are defined herein. Also disclosed are methods of using such compounds as inhibitors of signaling through Toll-like receptor 7, or 8, or 9, and pharmaceutical compositions comprising such compounds. These compounds are useful in treating inflammatory and autoimmune diseases.
Ligand-controlled reactivity plays an important role in transition-metal catalysis, enabling a vast number of efficient transformations to be discovered and developed. However, a single ligand is generally used to promote all steps of the catalytic cycle (e.g., oxidative addition, reductive elimination), a requirement that makes ligand design challenging and limits its generality, especially in relay