40150-91-2Relevant articles and documents
Catalytic α-Deracemization of Ketones Enabled by Photoredox Deprotonation and Enantioselective Protonation
Chen, Shuming,Gao, Anthony Z.,Ivlev, Sergei I.,Meggers, Eric,Nie, Xin,Ye, Chen-Xi,Zhang, Chenhao
supporting information, p. 13393 - 13400 (2021/09/03)
This study reports the catalytic deracemization of ketones bearing stereocenters in the α-position in a single reaction via deprotonation, followed by enantioselective protonation. The principle of microscopic reversibility, which has previously rendered this strategy elusive, is overcome by a photoredox deprotonation through single electron transfer and subsequent hydrogen atom transfer (HAT). Specifically, the irradiation of racemic pyridylketones in the presence of a single photocatalyst and a tertiary amine provides nonracemic carbonyl compounds with up to 97% enantiomeric excess. The photocatalyst harvests the visible light, induces the redox process, and is responsible for the asymmetric induction, while the amine serves as a single electron donor, HAT reagent, and proton source. This conceptually simple light-driven strategy of coupling a photoredox deprotonation with a stereocontrolled protonation, in conjunction with an enrichment process, serves as a blueprint for other deracemizations of ubiquitous carbonyl compounds.
Preparation method of organic carboxylic acid
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Paragraph 0077-0079, (2019/10/15)
The invention discloses a preparation method of organic carboxylic acid. The preparation method comprises the following steps that catalysts, olefins, water and solvents are added into a reaction container; CO is introduced; heating reaction is performed; after the reaction completion, separation is performed to obtain organic carboxylic acid; the catalysts comprise transition metal catalysts, ligands and catalysis assistants; the catalysis assistants comprise Lewis acid salt. The preparation method has the advantages that the dependency on protonic acid in the prior art is avoided; the Lewisacid salt is used as the catalysis assistant, so that the corrosion of a reaction system on equipment can be effectively prevented; the requirements on equipment are lowered. The preparation method has excellent substrate practicability; the operation steps are simple and fast; the reaction conditions are mild and are easy to control; the raw materials are cheap and can be easily obtained; the product yield and the product purity are high; the preparation method is suitable for large-scale industrial production; the normal/iso ratio of reaction products can be regulated and controlled throughthe catalysis assistants; the defects of regulating and controlling the normal/iso ratio of the reaction products by traditional phosphine ligands are overcome; the reaction progress of the reaction is simplified; the cost is favorably reduced.
Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations
Huang, Zijun,Cheng, Yazhe,Chen, Xipeng,Wang, Hui-Fang,Du, Chen-Xia,Li, Yuehui
supporting information, p. 3967 - 3970 (2018/04/23)
Impactful regioselectivity control is crucial for cost-effective chemical synthesis. By using cheap and abundant iron(iii) salts, the hydroxycarbonylations of both aromatic and aliphatic alkenes were significantly enhanced in both reactivity and selectivity (iso/n or n/iso up to >99:1). Moreover, Pd-catalyzed carbonylation selectivity can be switched from branched to linear by using different Fe(iii) salts. In addition, similar results were obtained for the carbonylation of secondary alcohols.
