1846-21-5Relevant academic research and scientific papers
Vinylogous Annulation Cascade Toward Stereoselective Synthesis of Highly Functionalized Indanone Derivatives
Bhajammanavar, Vinod,Mallik, Sumitava,Baidya, Mahiuddin
, p. 5472 - 5477 (2019)
A base promoted vinylogous annulation cascade of alkylidene malononitriles with cyclopentene-1,3-diones with a subsequent reduction sequence has been devised to furnish densely functionalized 3-hydroxyindanone scaffolds in high yields with excellent diastereoselectivity. Unlike preceding approaches that account for the formation of the pentanoid ring, this strategy features construction of the aromatic ring. The protocol is scalable, displays very broad substrates scope including late-stage functionalization of bioactive estrone, applicable to activated coumarin system, and is suitable to access an indenoquinoline derivative. (Figure presented.).
Iron-Catalyzed Photoredox Functionalization of Methane and Heavier Gaseous Alkanes: Scope, Kinetics, and Computational Studies
Zhang, Qingqing,Liu, Shuyang,Lei, Jinglan,Zhang, Yongqiang,Meng, Changgong,Duan, Chunying,Jin, Yunhe
, p. 1901 - 1906 (2022/03/27)
Herein, we report the development of the photocatalytic C-H functionalization of methane, ethane, and heavier gaseous alkanes with good yields and selectivity, broad scope (57 examples), mild conditions, and low cost. Kinetics and density functional theor
Convenient C(sp3)-H bond functionalisation of light alkanes and other compounds by iron photocatalysis
Duan, Chunying,Jin, Yunhe,Meng, Changgong,Wang, Lifang,Wang, Xinyao,Zhang, Qingqing
supporting information, p. 6984 - 6989 (2021/09/28)
Light alkanes are natural organic carbon sources and widely distributed in nature. Transforming them into value-added fine chemicals affords attractively economic and ecological benefits as well as enormous chemical challenges. Herein, we report a practical iron-catalysed photoredox system for C(sp3)-H transformation of ethane, propane, and other light alkanes to C-N and C-C bonds under ambient temperature. The present method with abundant and inexpensive iron salts as photocatalysts exhibits high catalytic efficiency (turnover number up to 8000), mild conditions, and the convenience of being purified and scaled up without chromatography. A photo-induced ligand-to-metal charge transfer between Fe(iii) and Cl- generates a highly active chlorine radical that sequentially acts as hydrogen atom transfer catalyst. Therefore, the sustainable, convenient, and environmentally friendly system will find wide applications in high-value-added transformation of natural alkanes with novel inspiration not only for organic synthesis, but also for designing catalytically active organic/inorganic materials. This journal is
C(sp3)-H functionalizations of light hydrocarbons using decatungstate photocatalysis in flow
Deng, Yuchao,Fagnoni, Maurizio,Guthrie, Duncan,Laudadio, Gabriele,No?l, Timothy,Nun?, Manuel,Ravelli, Davide,Sun, Yuhan,Wal, Klaas Van Der
, p. 92 - 96 (2020/09/03)
Direct activation of gaseous hydrocarbons remains a major challenge for the chemistry community. Because of the intrinsic inertness of these compounds, harsh reaction conditions are typically required to enable C(sp3)-H bond cleavage, barring potential applications in synthetic organic chemistry. Here, we report a general and mild strategy to activate C(sp3)-H bonds in methane, ethane, propane, and isobutane through hydrogen atom transfer using inexpensive decatungstate as photocatalyst at room temperature. The corresponding carbon-centered radicals can be effectively trapped by a variety of Michael acceptors, leading to the corresponding hydroalkylated adducts in good isolated yields and high selectivity (38 examples).
Microtubing-Reactor-Assisted Aliphatic C?H Functionalization with HCl as a Hydrogen-Atom-Transfer Catalyst Precursor in Conjunction with an Organic Photoredox Catalyst
Deng, Hong-Ping,Zhou, Quan,Wu, Jie
supporting information, p. 12661 - 12665 (2018/09/20)
Chlorine radical, which is classically generated by the homolysis of Cl2 under UV irradiation, can abstract a hydrogen atom from an unactivated C(sp3)?H bond. We herein demonstrate the use of HCl as an effective hydrogen-atom-transfer catalyst precursor activated by an organic acridinium photoredox catalyst under visible-light irradiation for C?H alkylation and allylation. The key to success relied on the utilization of microtubing reactors to maintain the volatile HCl catalyst. This photomediated chlorine-based C?H activation protocol is effective for a variety of unactivated C(sp3)?H bond patterns, even with primary C(sp3)?H bonds, as in ethane. The merit of this strategy is illustrated by rapid access to several pharmaceutical drugs from abundant unfunctionalized alkane feedstocks.
Facile metal free regioselective transfer hydrogenation of polarized olefins with ammonia borane
Yang, Xianghua,Fox, Thomas,Berke, Heinz
, p. 2053 - 2055 (2011/03/22)
Transfer hydrogenation of polarized olefins bearing strongly electron-withdrawing groups on one side of the double bond was achieved with ammonia borane under mild conditions without using a catalyst. Mechanistic studies proved the character of the direct H transfers proceeding stepwise with a unique hydroboration intermediate and hydride before proton transfer.
One-pot synthesis of malononitriles by free radical reactions of ylidenemalononitrile with Et3B and iodoalkane in a water-ether biphase medium
Tu, Zhijay,Lin, Chunchi,Jang, Yaochung,Jang, Yeong-Jiunn,Ko, Shengkai,Fang, Hulin,Liu, Ju-Tsung,Yao, Ching-Fa
, p. 6133 - 6137 (2007/10/03)
The one-pot synthesis of malononitrile derivatives 4, 6, and 7 in moderate to high yields by the reaction of ylidenemalononitriles 3, prepared in situ from carbonyl compounds 1 and malononitrile 2 in the presence of ammonium acetate in aqueous solution at
In Situ Generation and Synthetic Application of 2-Phenylbenzimidazoline to the Selective Reduction of Carbon-Carbon Double Bonds of Electron-Deficient Olefins
Chikashita, Hidenori,Nishida, Shuichi,Miyazaki, Makoto,Morita, Yasuhiro,Itoh, Kazuyoshi
, p. 737 - 746 (2007/10/02)
2-Phenylbenzimidazoline (PBI) as a mild, selective, and convenient reducing agent was efficiently generated in situ from o-phenylenediamine and benzaldehyde in alcohols.A generally applicable method for the selective reduction of carbon-carbon double bonds of a variety of electron-deficient olefins with an alcoholic solution of PBI is described.The reduction of α,β-unsaturated ketones to the corresponding saturated ketones could also be accomplished (but, less effectively) with PBI with the aid of a Lewis-acid catalyst. 1-Methyl-2-(o-nitrophenyl)benzimidazoline prepared and isolated by the reaction of o-nitrobenzaldehyde with N-methyl-o-phenylenediamine reduced benzylidenemalononitrile to give benzylmalononitrile and 1-methyl-2-(o-nitrophenyl)benzimidazoline in high yields.This shows the validity of PBI to be the actual reducing species in the present reduction system.From a mechanistic study, the present reductions could be interpreted in terms of a mechanism involving a synchronous transport of a pair of hydrogens or a sequential transfer of a hydride and a proton from PBI to the olefins.
