17133-51-6Relevant articles and documents
Enantioconvergent Cu-Catalyzed Radical C-N Coupling of Racemic Secondary Alkyl Halides to Access α-Chiral Primary Amines
Cheng, Jiang-Tao,Dong, Xiao-Yang,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Juan,Liu, Xin-Yuan,Luan, Cheng,Wang, Fu-Li,Wang, Li-Lei,Yang, Ning-Yuan,Zhang, Yu-Feng
supporting information, p. 15413 - 15419 (2021/09/30)
α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp3)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions. The reaction efficiently provides highly enantioenrichedN-alkyl sulfoximines (up to 99% yield and >99% ee) featuring secondary benzyl, propargyl, α-carbonyl alkyl, and α-cyano alkyl stereocenters. In addition, we have converted the masked α-chiral primary amines thus obtained to various synthetic building blocks, ligands, and drugs possessing α-chiral N-functionalities, such as carbamate, carboxylamide, secondary and tertiary amine, and oxazoline, with commonly seen α-substitution patterns. These results shine light on the potential of enantioconvergent radical cross-coupling as a general chiral carbon-heteroatom formation strategy.
A Chemoselective α-Oxytriflation Enables the Direct Asymmetric Arylation of Amides
Li, Jing,Berger, Martin,Zawodny, Wojciech,Simaan, Marwan,Maulide, Nuno
, p. 1883 - 1891 (2019/07/08)
Until recently, the direct oxidative oxysulfonylation of carbonyl compounds was limited to ketones. Here, we report the first direct oxytriflation of simple, non-activated amides. Amide umpolung with triflic anhydride and pyridine-N-oxide in the absence of external nucleophiles directly leads to the formation of reactive α-triflates in a single step, which provides a platform for the deployment of valuable downstream α-functionalization reactions. The utility of this method was demonstrated by in situ clean conversion to their corresponding bromides, as desirable starting materials for nickel-catalyzed deracemizing enantioselective arylation. This approach not only enables a telescoped asymmetric arylation of unsubstituted amides but also extends its scope because of the broad chemoselectivity and functional group tolerance of the method. Amides bearing a functional group in α-position are found in many natural products and drugs. The direct α-functionalization of amides is one of the most popular approaches to access these moieties. Classically, the α-functionalization of amides has been dominated by enolate chemistry; however, carboxamides are among the least C-H acidic carbonyl derivatives, and the presence of further carbonyl or carboxyl groups (such as esters and ketones) is therefore not usually tolerated. Here, we report the first direct α-oxytriflation of simple, non-activated amides using triflic anhydride and pyridine-N-oxide in the absence of external nucleophiles, which provides a platform for the deployment of valuable downstream α-functionalization reactions. The utility of this method was demonstrated by in situ clean conversion to the corresponding bromides, which are valuable starting materials for nickel-catalyzed deracemizing enantioselective arylation. A direct and chemoselective α-oxytriflation of simple and non-activated amides has been developed. This approach provides a platform for the development of valuable downstream α-functionalization reactions of amides. Furthermore, the combination of α-oxytriflation of amides and nickel-catalyzed Suzuki reaction provides an efficient approach for direct asymmetric α-arylation of simple amides.
Nickel-Catalyzed Asymmetric C-Alkylation of Nitroalkanes: Synthesis of Enantioenriched β-Nitroamides
Devannah, Vijayarajan,Sharma, Rajgopal,Watson, Donald A.
supporting information, p. 8436 - 8440 (2019/06/13)
A general catalytic method for asymmetric C-alkylation of nitroalkanes using nickel catalysis is described. This method enables the formation of highly enantioenriched β-nitroamides from readily available α-bromoamides using mild reaction conditions that are compatible with a wide range of functional groups. When combined with subsequent reactions, this method allows access to highly enantioenriched products with nitrogen-bearing fully substituted carbon centers.
