Decarboxylative Amination of SMAHOs by Dialkyl Azodicarboxylates

The decarboxylative addition of substituted malonic acid half oxyesters (SMAHOs) to dialkyl azodicarboxylates is described. The reaction was promoted by 1,4-diazabicyclo[2.2.2]octane (DABCO) as an organocatalyst in heated toluene. High yields of the coupling products were generally obtained, and the scope of the reaction proved rather important with the potential presence of functionalized side chains at the α-position, affording an original access to α-aminoester derivatives.     

Aminoazanium of DABCO: An Amination Reagent for Alkyl and Aryl Pinacol Boronates

The aminoazanium of DABCO (H₂N‐DABCO) has been developed as a general and practical amination reagent for the direct amination of alkyl and aryl pinacol boronates. This compound is stable and practical for use as a reagent. Various primary, secondary. and tertiary alkyl?Bpin and aryl?Bpin substrates were aminated to give the corresponding amine derivatives. The amination is stereospecific. The anti‐Markovnikov hydroamination of olefins was easily achieved by catalytic hydroboration with HBpin and in subsequent situ amination using H₂N‐DABCO. Moreover, the combination of 1,2‐diboration of olefins, using B₂pin₂, with this amination process achieved the unprecedented 1,2‐diamination of olefins. The amination protocol was also successfully extended to aryl pinacol boronates.     

Decarboxylative Benzylation of Aryl and Alkenyl Boronic Esters

The copper‐catalyzed decarboxylative benzylation of aryl and alkenyl boronic esters with electron‐deficient aryl acetates is reported. The oxidative coupling proceeds under mild, aerobic conditions and tolerates a host of potentially reactive electrophilic functional groups that would be problematic with traditional benzylation methods (aryl iodides and bromides, protic heteroatoms, aldehydes, Michael acceptors). A reaction pathway in which a benzylic nucleophile is generated by aryl acetate decarboxylation and in turn is intercepted by the catalyst to form diarylmethane products is supported by mechanistic studies.     

Catalytic One-Pot Reductive Amination of Carboxylic Acids

The broad applications of primary alkyl amines in various fields have spurred extensive interests in synthetic organic chemistry. Recently, the reductive amination of carboxylic acids has become an attractive and practical strategy for synthesizing primary alkyl amines, due to their wide availability and bench stability. However, the inherent stability and higher oxidation state of carboxylic acids render this new strategy with new challenges. This Concept provides a summary of the recent advancements in the reductive aminations of carboxylic acids, specifically focusing on the catalytic tactics, underlying mechanisms, and applications in the synthesis of valuable products.     

A Copper‐Catalyzed Decarboxylative Amination/Hydroamination Sequence: Switchable Synthesis of Functionalized Indoles

A copper‐catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth‐abundant metal catalyst, mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles. Moreover, experiments to demonstrate the synthetic potential of this methodology are performed.     

Copper-Catalyzed Amination of Aryl Halides with Aqueous Ammonia under Mild Conditions

A Cu(I) generated in situ from CuSO₄·5H₂O/sodium ascorbate catalyzed cross‐coupling reaction of aryl halides with aqueous ammonia for the synthesis of primary aromatic amines has been developed. Key to the success included the application of aqueous ammonia under a homogeneous condition.     

Electrophilic Amination: The Case of Nitrenoids

Among the numerous approaches and reagents employed for electrophilic amination, nitrenoids have long stayed out of the limelight. Here, we systematically review the discovery, structural features and chemical reactivity of these promising reagents. We highlight advances in applying the chemistry of nitrenoids as well as outline current limitations and future directions.     

Decarboxylative ipso Amination of Activated Benzoic Acids

In the presence of a bimetallic Pd/Cu system with 1,10‐phenanthroline as the ligand and either air or N‐methylmorpholine N‐oxide as the oxidant, electron‐deficient benzoic acids undergo oxidative decarboxylative coupling with unprotected amines. This operationally simple aniline synthesis is widely applicable with respect to the amine and gives good yields, even on multigram scale. The orthogonality of this reaction to other Pd‐catalyzed cross‐couplings allows the concise synthesis of multisubstituted arenes by sequential C?C, C?Cl, and C?N functionalizations. Mechanistic investigations suggest the intermediacy of a hypervalent Pd species.     

A Free‐Radical‐Promoted Stereospecific Decarboxylative Silylation of α,β‐Unsaturated Acids with Silanes

A stereospecific decarboxylative silylation of acrylic and propiolic acids with silanes was developed. This reaction represents the first example of decarboxylative C? Si bond formation and provides an efficient and convenient approach to various synthetically useful alkenyl and alkynyl organosilicon compounds through the reaction of α,β‐unsaturated acids with silanes. Spin‐trapping and EPR experiments support a radical addition/elimination process.     

Direct Catalytic Trifluoromethylthiolation of Boronic Acids and Alkynes Employing Electrophilic Shelf‐Stable N‐(trifluoromethylthio)phthalimide

A new and safe method for the synthesis of N‐(trifluoromethylthio)phthalimide, a convenient and shelf‐stable reagent for the direct trifluoromethylthiolation, has been developed. N‐(Trifluoromethylthio)phthalimide can be used as an electrophilic source of F₃CS⁺ and reacts readily with boronic acids and alkynes under copper catalysis. The utility of CF₃S‐containing molecules as biologically active agents, the mild reaction conditions employed, and the high tolerance of functional groups demonstrate the potential of this new methodology to be widely applied in organic synthesis as well as industrial pharmaceutical and agrochemical research and development.     

Decarboxylative Palladium(II)‐Catalyzed Synthesis of Aryl Amidines from Aryl Carboxylic Acids: Development and Mechanistic Investigation

A fast and convenient synthesis of aryl amidines starting from carboxylic acids and cyanamides is reported. The reaction was achieved by palladium(II)‐catalysis in a one‐step microwave protocol using [Pd(O₂CCF₃)₂], 6‐methyl‐2,2′‐bipyridyl and trifluoroacetic acid (TFA) in N‐methylpyrrolidinone (NMP), providing the corresponding aryl amidines in moderate to excellent yields. The protocol is very robust with regards to the cyanamide coupling partner but requires electron‐rich ortho‐substituted aryl carboxylic acids. Mechanistic insight was provided by a DFT investigation and direct ESI‐MS studies of the reaction. The results of the DFT study correlated well with the experimental findings and, together with the ESI‐MS study, support the suggested mechanism. Furthermore, a scale‐out (scale‐up) was performed with a non‐resonant microwave continuous‐flow system, achieving a maximum throughput of 11 mmol h^?1 by using a glass reactor with an inner diameter of 3 mm at a flow rate of 1 mL min^?1.     

钯催化卤代芳烃的胺化反应的研究进展

钯催化卤代芳烃的胺化是合成芳胺化合物的重要方法,综述了近年来钯催化卤代芳烃与胺等不同含氮化合物的胺化反应研究进展,重点讨论了钯催化剂配体的结构、反应物比例、溶剂及温度等因素对反应的影响.     

钯催化卤代芳烃的胺化反应研究

钯催化卤代芳烃胺化是形成Car-N的重要方法.配体的发展扩展了底物的适用范围, 提高了反应的选择性,实现了廉价易得的氯代芳烃的胺化,弱碱的使用提高了官能团的兼 容性,因此Pd催化芳胺化广泛应用于合成芳胺类化合物.本文以卤代芳烃为线索,对钯催化偶联胺化反应的研究进展进行了综述和展望.     

Nickel‐Catalyzed Decarboxylative C–Si Bond Formation: A Regioselective Cross‐Coupling Between Trialkyl Silanes and α,β‐Unsaturated Carboxylic Acids

This report presents the first example of nickel‐catalyzed mild decarboxylative cross‐coupling reaction for the regioselective formation of C–Si bond. An easily accessible and significantly stable Ni (dmg)₂ owes the role of key promoter. This reaction is highly functional group tolerant and offers α,β‐unsaturated silanes in synthetically useful yields. The reaction gives access to the successful utilization of otherwise difficult trialkyl silanes as coupling partners and operates at a moderate temperature, which is beneficial to deal with highly volatile silanes.