872045-32-4Relevant academic research and scientific papers
The catalytic asymmetric α-benzylation of aldehydes
List, Benjamin,Coric, Ilija,Grygorenko, Oleksandr O.,Kaib, Philip S. J.,Komarov, Igor,Lee, Anna,Leutzsch, Markus,Chandra Pan, Subhas,Tymtsunik, Andrey V.,Van Gemmeren, Manuel
, p. 282 - 285 (2014)
The first aminocatalyzed α-alkylation of α-branched aldehydes with benzyl bromides as alkylating agents has been developed. Using a sterically demanding proline derived catalyst, racemic α-branched aldehydes are reacted with alkylating agents in a DYKAT process to give the corresponding α-alkylated aldehydes with quaternary stereogenic centers in good yields and high enantioselectivities. A sterically demanding proline derivative promotes the first aminocatalyzed α-alkylation of α-branched aldehydes with benzyl bromides as alkylating agents. Racemic α-branched aldehydes react with alkylating agents in a DYKAT process to give the corresponding α-alkylated aldehydes with quaternary stereogenic centers in good yields and high enantioselectivities. Copyright
Palladium-catalyzed synthesis of α-aryl acetophenones from styryl ethers and aryl diazonium saltsviaregioselective Heck arylation at room temperature
Kandasamy, Jeyakumar,Lee, Yong Rok,Singh, Adesh Kumar,Venkatesh, Rapelly
supporting information, p. 7832 - 7837 (2021/09/28)
Preparation of α-aryl acetophenones from styryl ethers and aryldiazonium salts is described. The reaction is catalyzed by palladium acetate at room temperature in the absence of ligand and base. The developed method is highly attractive in terms of reaction conditions, substrate scope, functional group tolerance and yields. Synthetic applications of the present method are demonstrated by preparing α-aryl indoles and 3-aryl isocoumarin from styryl ethers.
Highly Enantioselective Synthesis of Propargyl Amide with Vicinal Stereocenters through Ir-Catalyzed Hydroalkynylation
Li, Bi-Jie,Zhang, Su-Lei,Zhang, Wen-Wen
supporting information, p. 6874 - 6880 (2020/03/19)
Chiral propargyl amines are valuable synthetic intermediates for the preparation of biologically active compounds and functionalized amines. Catalytic methods to access propargyl amines containing vicinal stereocenters with high diastereoselectivity are particularly rare. We report an unprecedented strategy for the synthesis of enantioenriched propargyl amines with two stereogenic centres. An iridium complex, ligated by a phosphoramidite ligand, catalyzes the hydroalkynylation of β,β-disubstituted enamides to afford propargyl amides in a highly regio-, diastereo-, and enantioselective fashion. Stereodivergent synthesis of all four possible stereoisomers was achieved using this strategy.
Nickel-Catalyzed Desymmetric Hydrogenation of Cyclohexadienones: An Efficient Approach to All-Carbon Quaternary Stereocenters
You, Cai,Li, Xiuxiu,Gong, Quan,Wen, Jialin,Zhang, Xumu
supporting information, p. 14560 - 14564 (2019/10/11)
Nickel-catalyzed desymmetric hydrogenation has been achieved. With the Ni(OTf)2/(S,S)-Ph-BPE system, a series of ?,?-disubstituted cyclohexadienones were transformed to the corresponding cyclohexenones with a chiral all-carbon quaternary center at the γposition in high yields (92-98%) and excellent enantioselectivities (92%-99% ee). This catalytic system can also tolerate the desymmetric reaction of spirocarbocyclic cyclohexadienones to produce the corresponding cyclohexenones bearing a chiral spiro quaternary carbon with high yields (94%-98%) and ee values (96%-99% ee). Furthermore, this methodology provides an efficient and concise synthetic route to the intermediate of natural products cannabispirenones A and B.
Copper-catalyzed vinylogous aerobic oxidation of unsaturated compounds with air
Zhang, Hai-Jun,Schuppe, Alexander W.,Pan, Shi-Tao,Chen, Jin-Xiang,Wang, Bo-Ran,Newhouse, Timothy R.,Yin, Liang
supporting information, p. 5300 - 5310 (2018/04/24)
A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of β,γ- and α,β-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity, and good functional group tolerance. This method is additionally capable of oxidizing β,γ- and α,β-unsaturated aldehydes, ketones, amides, nitriles, and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. Tetramethylguanidine (TMG) was found to be crucial in its role as a base, but we also speculate that it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst. Mechanistic experiments conducted suggest a plausible reaction pathway via an allylcopper(II) species. Finally, the breadth of scope and power of this methodology are demonstrated through its application to complex natural product substrates.
Asymmetric α-Allylation of Aldehydes with Alkynes by Integrating Chiral Hydridopalladium and Enamine Catalysis
Su, Yong-Liang,Li, Lu-Lu,Zhou, Xiao-Le,Dai, Zhen-Yao,Wang, Pu-Sheng,Gong, Liu-Zhu
supporting information, p. 2403 - 2406 (2018/04/27)
A palladium-catalyzed asymmetric α-allylation of aldehydes with alkynes has been established by integrating the catalysis of enamine and chiral hydridopalladium complex that is reversibly formed from the oxidative addition of Pd(0) to chiral phosphoric acid. The ternary catalyst system, consisting of an achiral palladium complex, a primary amine, and a chiral phosphoric acid allows the reaction to tolerate a wide scope of α,α-disubstituted aldehydes and alkynes, affording the corresponding allylation products in high yields and with excellent levels of enantioselectivity.
Rhodium-catalyzed asymmetric hydrogenation of β-branched enamides for the synthesis of β-stereogenic amines
Zhang, Jian,Liu, Chong,Wang, Xingguang,Chen, Jianzhong,Zhang, Zhenfeng,Zhang, Wanbin
supporting information, p. 6024 - 6027 (2018/06/18)
Using a rhodium complex of a bisphosphine ligand (R)-SDP, β-branched simple enamides with a (Z)-configuration were hydrogenated to β-stereogenic amines in quantitative yields and with excellent enantioselectivities (88-96% ee).
Effective construction of quaternary stereocenters by highly enantioselective α-amination of branched aldehydes
Fu, Ji-Ya,Xu, Xiao-Ying,Li, Yan-Chun,Huang, Qing-Chun,Wang, Li-Xin
supporting information; experimental part, p. 4524 - 4526 (2010/11/21)
A highly efficient enantioselective α-amination of branched aldehydes with azadicarboxylates promoted by chiral proline-derived amide thiourea bifunctional catalysts was developed for the first time, affording the adducts bearing quaternary stereogenic centers with excellent yields (up to 99%) and enantioselectivities (up to 97% ee).
The proline-catalyzed asymmetric amination of branched aldehydes
Baumann, Thomas,Vogt, Henning,Braese, Stefan
, p. 266 - 282 (2007/10/03)
An efficient access to configurationally stable α,β- disubstituted α-amino aldehydes, oxazolidinones, and α-amino acids has been presented. Starting from simple and easily available racemic aldehydes, the α-aminated products were obtained using azodicarboxylates as the nitrogen source in up to 86 % ee and moderate to excellent yield. These products could further be converted both into the corresponding α-amino alcohols and, depending on the residue of the azodicarboxylates and the reaction conditions, into the oxazolidinones. On the other hand, oxidation towards the carboxylic acid and cleavage of the hydrazide bond under mild conditions revealed the free α-alkylated phenylglycine derivative. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
