Cyclic Ureate Tantalum Catalyst for Preferential Hydroaminoalkylation with Aliphatic Amines: Mechanistic Insights into Substrate Controlled Reactivity
作者:Pargol Daneshmand、Sorin-Claudiu Roşca、Rosalie Dalhoff、Kejun Yin、Rebecca C. DiPucchio、Ryan A. Ivanovich、Dilan E. Polat、André M. Beauchemin、Laurel L. Schafer
DOI:10.1021/jacs.0c04579
日期:2020.9.16
accessible, N,O-chelated cyclic ureate tantalum catalyst was prepared and characterized by X-ray crystallography. This opti-mized catalyst can be used for the hydroaminoalkylation of 1-octene with a variety of aryl and alkyl amines, but notably enhanced catalytic activity can be realized with challenging N-alkyl secondary amine substrates. This catalyst offers turnover frequencies of up to 60 h-1, affording
Catalytic and Atom-Economic Csp3
−Csp3
Bond Formation: Alkyl Tantalum Ureates for Hydroaminoalkylation
作者:Rebecca C. DiPucchio、Sorin-Claudiu Roşca、Laurel L. Schafer
DOI:10.1002/anie.201712668
日期:2018.3.19
achieved by rapid C−H alkylation of unprotected secondary arylamines with unactivated alkenes. The combination of Ta(CH2SiMe3)3Cl2, and a ureate N,O‐chelating‐ligand salt gives catalytic systems prepared in situ that can realize high yields of β‐alkylated aniline derivatives from either terminal or internal alkene substrates. These new catalyst systems realize C−H alkylation in as little as one hour
Fast Titanium‐Catalyzed Hydroaminomethylation of Alkenes and the Formal Conversion of Methylamine
作者:Jens Bielefeld、Sven Doye
DOI:10.1002/anie.202001111
日期:2020.4.6
The scientific interest in catalytic hydroaminoalkylation reactions of alkenes has vastly increased over the past decade, but these reactions have struggled to become a viable option for general laboratory or industrial use because of reaction times of several days. The titanium-based catalytic system introduced in this work not only reduces the reaction time by several orders of magnitude, into the
[Ind<sub>2</sub>TiMe<sub>2</sub>]: A Catalyst for the Hydroaminomethylation of Alkenes and Styrenes
作者:Raphael Kubiak、Insa Prochnow、Sven Doye
DOI:10.1002/anie.200906557
日期:2010.3.29
Metal‐catalyzed hydroaminomethylations of styrenes, which take place by CH bond activation, can be achieved in the presence of the catalyst [Ind2TiMe2] (Ind=η5‐indenyl). Corresponding reactions of 1‐alkenes with N‐methylanilines performed at temperatures between 80 °C and 105 °C usually take place with regioselectivities of better than 99:1 in favor of the branched product.
Direct, Catalytic Hydroaminoalkylation of Unactivated Olefins with <i>N</i>-Alkyl Arylamines
作者:Seth B. Herzon、John F. Hartwig
DOI:10.1021/ja0718366
日期:2007.5.1
arylamine α-C−H bonds across olefins is reported. These reactions occur with mono- and 2,2-disubstituted olefins to form the branched insertion products in high yield and regioselectivity. The reactions encompass additions of the α-C−H bonds of cyclic and acyclic amines, as well as intramolecular additions. NMR studies indicate that the starting homoleptic, Ta(NMe2)5 precatalyst converts to bis- and tris(N-methylanilide)