47644-69-9Relevant articles and documents
Oxidation of BINOLs by Hypervalent Iodine Reagents: Facile Synthesis of Xanthenes and Lactones
Zhang, Huaiyuan,Wirth, Thomas
supporting information, (2022/03/17)
Xanthene derivatives have broad applications in medicines, fluorescent probes, dyes, food additives, etc. Therefore, much attention was focused on developing the synthetic methods to prepare these compounds. Binaphthyl-based xanthene derivatives were prepared through the oxidation of BINOLs promoted by the hypervalent iodine reagent iodosylbenzene (PhIO). Nine-membered lactones were obtained through a similar oxidative reaction when iodoxybenzene (PhIO2) was used. Additionally, one-pot reactions of BINOLs, PhIO and nucleophiles such as alcohols and amines were also investigated to provide alkoxylated products and amides in good to excellent yields.
Accurate Understanding the Catalytic Role of MnO2 in the Oxidative-Coupling of 2-naphthols into 1,1′-bi-2-naphthols
Wu, Yuting,Yang, Long,Wu, Bo,Li, Jie,Liu, Binyao,Ke, Gaili,Dong, Faqin,Zhou, Yong,He, Huichao
, p. 901 - 908 (2020/08/17)
Abstract: It has been reported that β-MnO2 has photocatalytic activity for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols. Nevertheless, it is hard to exclude the possibility that the oxidative-coupling of 2-naphthols is initiated by β-MnO2 catalysis in dark due to the insufficient investigations in the related reports. In the present work, the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols with different phases MnO2 catalysis in dark and under visible-light irradiation were systematically investigated. The results revealed that the oxidative-coupling of 2-naphthols is jointly initiated by MnO2 catalysis and O2-oxidation, not by MnO2 photocatalysis. Among the α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2 catalysis, β-MnO2 catalysis has the optimal performance, its selectivity for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols is close to 100%, and its catalytic capacity could be well retained after multiple using. Our findings provide comprehensive and accurate understanding the catalytic role of MnO2 for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols. Graphic Abstract: In the present work, the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols was proved to be jointly initiated by MnO2 catalysis and O2-oxidation, not by MnO2 photocatalysis. β-MnO2 has the optimal catalytic activity for the oxidative-coupling of 2-naphthols relative to α-MnO2, γ-MnO2 and δ-MnO2. [Figure not available: see fulltext.]
Isothiourea-Catalysed Regioselective Acylative Kinetic Resolution of Axially Chiral Biaryl Diols
Qu, Shen,Greenhalgh, Mark D.,Smith, Andrew D.
supporting information, p. 2816 - 2823 (2019/02/05)
An operationally simple isothiourea-catalysed acylative kinetic resolution of unprotected 1,1′-biaryl-2,2′-diol derivatives has been developed to allow access to axially chiral compounds in highly enantioenriched form (s values up to 190). Investigation of the reaction scope and limitations provided three key observations: i) the diol motif of the substrate was essential for good conversion and high s values; ii) the use of an α,α-disubstituted mixed anhydride (2,2-diphenylacetic pivalic anhydride) was critical to minimize diacylation and give high selectivity; iii) the presence of substituents in the 3,3′-positions of the diol hindered effective acylation. This final observation was exploited for the highly regioselective acylative kinetic resolution of unsymmetrical biaryl diol substrates bearing a single 3-substituent. Based on the key observations identified, acylation transition state models have been proposed to explain the atropselectivity of this kinetic resolution.
