scholarly journals Asymmetric Synthesis of Propargylic alfa-Chiral Tertiary Amines by Reductive Alkynylation of Tertiary Amides Using Ir/Cu Tandem Catalysis

2021 ◽  
Author(s):  
Toolika Agrawal ◽  
Kimberly Perez-Morales ◽  
Jermaine Cort ◽  
Joshua Sieber
Keyword(s):  
Asymmetric Synthesis ◽  
Catalyst System ◽  
Tertiary Amines ◽  
Tandem Catalysis ◽  
Tertiary Amides

The development of an asymmetric protocol for the reductive alkynylation of amides to access important alfa-chiral tertiary propargylic amines is reported using tandem Ir-catalyzed hydrosilylation/enantioselective Cu-catalyzed alkynylation. The reaction utilizes a Cu/PyBox catalyst system in the alkynylation step to achieve asymmetry and affords excellent yields with moderate to good levels of enantiocontrol while employing low Ir-catalyst loadings (0.5 mol %).

Mechanistic Insights into Fe Catalyzed α-C-H Oxidations of Tertiary Amines

2019 ◽  
Author(s):  
Christopher J. Legacy ◽  
Frederick T. Greenaway ◽  
Marion Emmert
Keyword(s):  
Free Radical ◽  
Catalytic Mechanism ◽  
Catalyst System ◽  
Oxidation Products ◽  
Tertiary Amines ◽  
Catalyst Activation ◽  
Rate Determining Step ◽  
Fe Catalyst ◽  
Ligand Coordination ◽  
Rate Kinetics

We report detailed mechanistic investigations of an iron-based catalyst system, which allows the α-C-H oxidation of a wide variety of amines, including acyclic tertiary aliphatic amines, to afford dealkylated or amide products. In contrast to other catalysts that affect α-C-H oxidations of tertiary amines, the system under investigation employs exclusively peroxy esters as oxidants. More common oxidants (e.g. tBuOOH) previously reported to affect amine oxidations via free radical pathways do not provide amine α-C-H oxidation products in combination with the herein described catalyst system. Motivated by this difference in reactivity to more common free radical systems, the investigations described herein employ initial rate kinetics, kinetic profiling, Eyring studies, kinetic isotope effect studies, Hammett studies, ligand coordination studies, and EPR studies to shed light on the Fe catalyst system. The obtained data suggest that the catalytic mechanism proceeds through C-H abstraction at a coordinated substrate molecule. This rate-determining step occurs either at an Fe(IV) oxo pathway or a 2-electron pathway at a Fe(II) intermediate with bound oxidant. We further show via kinetic profiling and EPR studies that catalyst activation follows a radical pathway, which is initiated by hydrolysis of PhCO3 tBu to tBuOOH in the reaction mixture. Overall, the obtained mechanistic data support a non-classical, Fe catalyzed pathway that requires substrate binding, thus inducing selectivity for α-C-H functionalization.<br>

Asymmetric Synthesis of Less Accessible α-Tertiary Amines from Alkynyl Z- Ketimines

2017 ◽  
Vol 56 (51) ◽  
pp. 16293-16296 ◽  
Author(s):  
Taichi Kano ◽  
Yusuke Aota ◽  
Keiji Maruoka
Keyword(s):  
Asymmetric Synthesis ◽  
Tertiary Amines

scholarly journals The Asymmetric Synthesis of (-)-Pumiliotoxin C Using Tandem Catalysis.

ChemInform ◽  
2005 ◽  
Vol 36 (6) ◽  
Author(s):  
Ewold W. Dijk ◽  
Lavinia Panella ◽  
Pedro Pinho ◽  
Robert Naasz ◽  
Auke Meetsma ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Tandem Catalysis ◽  
Pumiliotoxin C

The copper-catalyzed aerobic oxidative amidation of tertiary amines

2015 ◽  
Vol 51 (99) ◽  
pp. 17596-17599 ◽  
Author(s):  
Hui-Cheng Cheng ◽  
Wen-Jun Hou ◽  
Zeng-Wen Li ◽  
Ming-Yu Liu ◽  
Bing-Tao Guan
Keyword(s):  
Efficient Method ◽  
Tertiary Amines ◽  
Oxidative Amidation ◽  
Tertiary Amides

A general and efficient method for the synthesis of tertiary amides has been developed via the copper-catalyzed aerobic oxidative amidation of tertiary amines.

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