824-91-9Relevant articles and documents
Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
supporting information, p. 5022 - 5037 (2021/05/04)
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Rhodium(II)-Catalyzed Aryl C?H Carboxylation of 2-Pyridylphenols with CO2
Cai, Zhihua,Li, Shangda,Gao, Yuzhen,Li, Gang
supporting information, p. 4005 - 4011 (2018/09/20)
A protocol for C?H carboxylation of electron-deficient 2-pyridylphenols with CO2 through a Rh(II)-catalyzed C?H bond activation under redox-neutral conditions has been developed. A suitable phosphine ligand was crucial for this reaction. This m
Enantioselective and Regioselective Hydroetherification of Alkynes by Gold-Catalyzed Desymmetrization of Prochiral Phenols with P-Stereogenic Centers
Zheng, Yin,Guo, Linna,Zi, Weiwei
supporting information, p. 7039 - 7043 (2018/11/24)
The gold(I)-catalyzed enantioselective hydroetherification of alkynes was achieved via desymmetrization of prochiral bisphenols bearing P-stereogenic centers. (S)-DTBM-Segphos(AuCl)2/AgNTf2 proved to be a highly efficient catalyst system for this transformation, affording P-chiral cyclic phosphine oxides in good yields with high enantioselectivities (with up to 99% ee). The same catalyst system allowed for the enantioselective desymmetrization of dialkynes. Synthetic transformations of the cyclization products afforded other P-chiral molecules with high enantiospecificity.
Electrochemical methoxymethylation of alcohols-a new, green and safe approach for the preparation of MOM ethers and other acetals
Luo, Xiya,Ma, Xiaofeng,Lebreux, Frédéric,Markó, István E.,Lam, Kevin
supporting information, p. 9969 - 9972 (2018/09/11)
A new, green, safe, cost-effective and highly efficient electrochemical approach for the methoxymethylation of alcohols and phenols was successfully developed. The methodology was also applied to the synthesis of substituted acetals.
Total synthesis of [13C]2-, [13C]3-, and [13C]5-isotopomers of xanthohumol, the principal prenylflavonoid from hops
Ellinwood, Duncan C.,El-Mansy, Mohamed F.,Plagmann, Layhna S.,Stevens, Jan F.,Maier, Claudia S.,Gombart, Adrian F.,Blakemore, Paul R.
, p. 639 - 648 (2017/11/27)
Xanthohumol [(E)-6′-methoxy-3′-(3-methylbuten-2-yl)-2′,4′,4″-trihydroxychalcone], he principal prenylated flavonoid from hops, has a complex bioactivity profile, and 13C-labeled isotopomers of this compound are of potential use as molecular probes and as analytical standards to study metabolism and mode of action. 1,3-[13C]2-Xanthohumol was prepared by an adaptation of the total synthesis of Khupse and Erhardt in 7 steps and 5.7% overall yield from phloroglucinol by a route incorporating a cascade Claisen-Cope rearrangement to install the 3′-prenyl moiety from a 5′-prenyl aryl ether and an aldol condensation between 1-[13C]-2′,4′-bis(benzyloxymethyloxy)-6′-methoxy-3′-(3-methylbuten-2-yl)acetophenone and 1′-[13C]-4-(methoxymethyloxy)benzaldehyde. The 13C-atom in the methyl ketone was derived from 1-[13C]-acetyl chloride while that in the aryl aldehyde was derived from [13C]-iodomethane. Tri- and penta-13C-labeled xanthohumols were similarly prepared by applying minor modifications to the route.
Bismuth trichloride–mediated cleavage of phenolic methoxymethyl ethers
Obaro-Best, Oghale,Reed, Jack,Norfadilah, Alya A. F. B.,Monahan, Ryan,Sunasee, Rajesh
supporting information, p. 586 - 593 (2016/06/08)
A simple and efficient method for removal of phenolic methoxymethyl ethers in the presence of 30?mol% of bismuth trichloride in acetonitrile/water is described. Notable features of the cleavage protocol entail use of an ecofriendly bismuth reagent, ease of handling, low cost, operational simplicity, and good functional group compatibility. A number of structurally varied phenolic methoxymethyl ethers were cleaved in good to excellent yields.
Enantiodivergent Atroposelective Synthesis of Chiral Biaryls by Asymmetric Transfer Hydrogenation: Chiral Phosphoric Acid Catalyzed Dynamic Kinetic Resolution
Mori, Keiji,Itakura, Tsubasa,Akiyama, Takahiko
supporting information, p. 11642 - 11646 (2016/10/24)
Reported herein is an enantiodivergent synthesis of chiral biaryls by a chiral phosphoric acid catalyzed asymmetric transfer hydrogenation reaction. Upon treatment of biaryl lactols with aromatic amines and a Hantzsch ester in the presence of chiral phosp
P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
, p. 1699 - 1712 (2016/07/27)
P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
Pd-Catalyzed Cross-Coupling of Aryllithium Reagents with 2-Alkoxy-Substituted Aryl Chlorides: Mild and Efficient Synthesis of 3,3′-Diaryl BINOLs
Castelló, Luis M.,Hornillos, Valentín,Vila, Carlos,Giannerini, Massimo,Fa?anás-Mastral, Martín,Feringa, Ben L.
supporting information, p. 62 - 65 (2015/07/28)
Palladium-catalyzed cross-coupling of aryllithium reagents with 2-alkoxy-substituted aryl chlorides is described. The reactions proceed under mild conditions with short reaction times and provide a wide range of 2-alkoxy-substituted biaryls. This new methodology is applied to the efficient preparation of 3,3′-diaryl BINOLs and represents the first synthesis of this important class of chiral compounds from the corresponding 3,3′-dichloro BINOLs. (Chemical Equation Presented).
Two novel tetracycles, cassibiphenols A and B from the flowers of Cassia siamea
Deguchi, Jun,Sasaki, Tadahiro,Hirasawa, Yusuke,Kaneda, Toshio,Kusumawati, Idha,Shirota, Osamu,Morita, Hiroshi
, p. 1362 - 1365 (2014/03/21)
Chemical investigation of the flowers of Cassia siamea (Leguminosae), resulted in the isolation of two novel tetracycles connecting 5-(2-hydroxypropyl)benzene-1,3-diol, cassibiphenols A (1) and B (2). The structures were elucidated by analysis of the 1D, 2D NMR, and HRMS spectra. Synthesis of a tetracyclic core of 1 and 2 led to determine the absolute configuration of 1 and C-12 of 2.
