2341-21-1Relevant academic research and scientific papers
Palladium-Catalyzed Reductive Aminocarbonylation of Benzylammonium Triflates with o-Nitrobenzaldehydes for the Synthesis of 3-Arylquinolin-2(1 H)-ones
Liu, Yongzhu,Qi, Xinxin,Wu, Xiao-Feng
, p. 13824 - 13832 (2021/10/12)
A palladium-catalyzed straightforward procedure for the synthesis of 3-arylquinolin-2(1H)-ones has been developed. The synthesis proceeds through a palladium-catalyzed reductive aminocarbonylation reaction of benzylic ammonium triflates with o-nitrobenzaldehydes, and a wide range of 3-arylquinolin-2(1H)-ones was obtained in moderate to good yields with very good functional group compatibility.
The Role of Fluorine Substituents in the Regioselectivity of Intramolecular C-H Bond Functionalization of Benzylamines at Palladium(II)
Milani, Jessica,Pridmore, Natalie E.,Whitwood, Adrian C.,Fairlamb, Ian J.S.,Perutz, Robin N.
supporting information, p. 4376 - 4386 (2015/09/22)
The effect of fluorine substituents on the regioselectivity of intramolecular reactions of mono- and difluorinated N,N-dimethylbenzylamines (1a-f) at palladium, to form palladacycles di-μ-acetatobis[o-dimethylaminomethyl-n-fluorophenyl-C,N)dipalladium(II) (2a-f) and di-μ-chlorobis[o-dimethylaminomethyl-n-fluorophenyl-C,N)dipalladium(II) (3a-e), has been investigated. When fluorinated substrates with two sites available for the C-H functionalization (1c and 1e) undergo cyclopalladation via a CMD mechanism (acetate-bridged palladacycles), they do not exhibit regioselectivity. In contrast, the same substrates exhibit complete regioselectivity for the C-H functionalization para to fluorine in cyclopalladation reactions that proceed via an SEAr mechanism (involving chloride-bridged palladacycles). X-ray crystal structures were obtained for all the palladacycles synthesized, and a structural analysis showed that the number and the position of the fluorine atoms on the aromatic ring have a marked effect on the "clamshell" structure of the acetate-bridged palladacycles. By contrast, there is no great variation in the structures of the planar chloride-bridged palladacycles.
Simple Amine-Directed Meta-Selective C-H Arylation via Pd/Norbornene Catalysis
Dong, Zhe,Wang, Jianchun,Dong, Guangbin
supporting information, p. 5887 - 5890 (2015/05/27)
Herein we report a highly meta-selective C-H arylation using simple tertiary amines as the directing group. This method takes advantage of Pd/norbornene catalysis, offering a distinct strategy to control the site selectivity. The reaction was promoted by commercially available AsPh3 as the ligand and a unique "acetate cocktail". Aryl iodides with an ortho electron-withdrawing group were employed as the coupling partner. A wide range of functional groups, including some heteroarenes, are tolerated under the reaction conditions. In addition, the amine directing group can be easily installed and transformed to other common versatile functional groups. We expect this C-H functionalization mode to have broad implications for developing other meta-selective transformations beyond this work.
Iridium-catalyzed, substrate-directed C-H borylation reactions of benzylic amines
Roering, Andrew J.,Hale, Lillian V. A.,Squier, Phillip A.,Ringgold, Marissa A.,Wiederspan, Emily R.,Clark, Timothy B.
supporting information; experimental part, p. 3558 - 3561 (2012/08/29)
The iridium-catalyzed arene C-H borylation reaction of benzylic amines has been developed, which inverts the typical steric-controlled product distribution to provide ortho-substituted boronate esters. Picolylamine was found to be an ideal ligand to replace 4,4′-di-tert-butylbipyridine to induce the directing effect. Preliminary experiments are consistent with a mechanism involving dissociation of one amine of the hemilabile diamine ligand.
Superelectrophilic intermediates in nitrogen-directed aromatic borylation
De Vries, Timothy S.,Prokofjevs, Aleksandrs,Harvey, Jeremy N.,Vedejs, Edwin
supporting information; experimental part, p. 14679 - 14687 (2010/01/06)
The first examples of borylation under conditions of borenium ion generation from hydrogen-bridged boron cations are described. The observable H-bridged cations are generated by hydride abstraction from N,N-dimethylamine boranes Ar(CH2)nNMe2BH3 using Ph3C+ (C6F5)4B - (TrTPFPB) as the hydride acceptor. In the presence of excess TrTPFPB, the hydrogen-bridged cations undergo internal borylation to afford cyclic amine borane derivatives with n = 1-3. The products are formed as the corresponding cyclic borenium ions according to reductive quenching experiments and 11B and 1H NMR spectroscopy in the case with Ar = C6H5 and n = 1. The same cyclic borenium cation is also formed from the substrate with Ar = o-C6H4SiMe3 via desilylation, but the analogous system with Ar = o-C6H 4CMe3 affords a unique cyclization product that retains the tert-butyl substituent. An ortho-deuterated substrate undergoes cyclization with a product-determining isotope effect of kH/kD 2.8. Potential cationic intermediates have been evaluated using B3LYP/6-31G* methods. The computations indicate that internal borylation from 14a occurs via a C-H insertion transition state that is accessible from either the borenium π complex or from a Wheland intermediate having nearly identical energy. The Ar = o-C6H4SiMe3 example strongly favors formation of the Wheland intermediate, and desilylation occurs via internal SiMe3 migration from carbon to one of the hydrides attached to boron.
