Planar‐Chiral [2.2]Paracyclophane‐Based Pyridonates as Ligands for Tantalum‐Catalyzed Hydroaminoalkylation
作者:Carolin Braun、Martin Nieger、Stefan Bräse、Laurel L. Schafer
DOI:10.1002/cctc.201900416
日期:2019.11.7
By using planarchiral [2.2]paracyclophane‐containing N,O‐chelating ligands for tantalum‐catalyzedhydroaminoalkylation, one of the most versatile catalytic systems for this reaction to date was obtained. Convenient Csp3−Csp3 bond formation of amines with terminal and internal alkenes was enabled by the same in situ synthesized catalytic system of [2.2]paracyclophane‐basedpyridonates and Ta(CH2TMS)3Cl2
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
Phosphoramidate Tantalum Complexes for Room-Temperature CH Functionalization: Hydroaminoalkylation Catalysis
作者:Pierre Garcia、Ying Yin Lau、Mitchell R. Perry、Laurel L. Schafer
DOI:10.1002/anie.201304153
日期:2013.8.26
A cooled reaction: Phosphoramidate–ClTaMe3 complexes promote the first example of room‐temperature hydroaminoalkylation catalysis. This reaction can be realized under solvent‐free conditions and with challenging substrates such as styrenes and dialkyl amines. When using a vinylsilane substrate, for the first time the linear regioisomer is obtained preferentially using a Group 5 metal. TBS=tert‐butyldimethylsilyl
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