16606-47-6Relevant articles and documents
Synthesis and reactivity of a zwitterionic palladium allyl complex supported by a perchlorinated carboranyl phosphine
Estrada, Jess,Woen, David H.,Tham, Fook S.,Miyake, Garret M.,Lavallo, Vincent
, p. 5142 - 5144 (2015)
A zwitterionic palladium complex of a phosphine bearing a perchlorinated carba-closo-dodecaborate anion as a ligand substituent is reported. A single-crystal X-ray diffraction study reveals that, in the solid state, one of the chlorides of the carborane cage occupies a coordination site of the square-planar complex. However, in solution, the P-carborane bond of the ligand is rapidly rotating at temperatures as low as -90 °C, which demonstrates the carborane substituent's weak coordinative ability even though this anion is covalently linked to the phosphine ligand. The complex is thermally stable and catalyzes the vinyl addition polymerization of norbornene.
Electrochemical-induced radical allylation via the fragmentation of alkyl 1,4-dihydropyridines
Chen, Xiaoping,Luo, Xiaosheng,Wang, Ping
, (2022/02/02)
Aldehydes are abundant chemical motifs presented in natural products and pharmaceuticals. As a radical precursor, its application is limited. Dihydropyridines (DHPs) can act as masked aldehydes, providing alkyl radicals under the activation of Lewis acid, heat, SET oxidant and light irradiation. Herein, we report the direct activation of 4-alkyl DHPs via single electron transfer at the anode. C–C bond homolysis at the C4-position of DHP generated the corresponding alkyl radical, which was captured subsequently by 2-phenyl and 2-ethoxy carbonyl allyl bromide. The following intramolecular elimination reaction afforded 20 different radical allylation products bearing various alkyl substituents with yields up to 92%.
Intermolecular [4 + 2] process of N-acyliminium ions with simple olefins for construction of functional substituted-1,3-oxazinan-2-ones
Han, Xiaoli,Nie, Xiaodi,Feng, Yiman,Wei, Bangguo,Si, Changmei,Lin, Guoqiang
supporting information, p. 3526 - 3530 (2021/06/12)
An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones skeleton has been developed through the reaction of semicyclic N,O-acetals 4a and 4b with 1,1-disubstituted ethylenes 5 or 8. As a result of such a [4 +
Iron-Catalyzed Highly Enantioselective Hydrogenation of Alkenes
Lu, Dongpo,Lu, Peng,Lu, Zhan,Ren, Xiang,Sun, Yufeng,Xu, Haofeng
supporting information, p. 12433 - 12438 (2021/08/23)
Here, we reported for the first time an iron-catalyzed highly enantioselective hydrogenation of minimally functionalized 1,1-disubstituted alkenes to access chiral alkanes with full conversion and excellent ee. A novel chiral 8-oxazoline iminoquinoline ligand and its iron complex have been designed and synthesized. This protocol is operationally simple by using 1 atm of hydrogen gas and shows good functional group tolerance. A primary mechanism has been proposed by the deuterium-labeling experiments.
A donor-acceptor complex enables the synthesis of: E -olefins from alcohols, amines and carboxylic acids
Chen, Kun-Quan,Shen, Jie,Wang, Zhi-Xiang,Chen, Xiang-Yu
, p. 6684 - 6690 (2021/05/31)
Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies require a transition metal catalyst, a ligand or an expensive photocatalyst, with the challenges of controlling the region- and stereoselectivities remaining. Herein, we present a fundamentally distinct strategy enabled by electron donor-acceptor (EDA) complexes, for the selective synthesis of olefins from these simple and easily available starting materials. The conversions took place via photoactivation of the EDA complexes of the activated substrates with alkali salts, followed by hydrogen atom elimination from in situ generated alkyl radicals. This method is operationally simple and straightforward and free of photocatalysts and transition-metals, and shows high regio- and stereoselectivities.
Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
supporting information, p. 8910 - 8917 (2020/12/23)
Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
Nickel-Catalyzed Benzylation of Aryl Alkenes with Benzylamines via C-N Bond Activation
Yu, Hui,Hu, Bin,Huang, Hanmin
, p. 13922 - 13929 (2018/11/23)
We have developed the first example of nickel-catalyzed Heck-type benzylation of aryl olefins with various benzylamines as benzyl electrophiles, and the benzylic C-N bond cleavage was efficiently promoted by the amine-I2 charge transfer complex (CT complex). The combination of low-cost NiCl2 and I2 has been found to facilitate Heck reaction of tertiary benzylamines and alkenes into various benzyl-substituted alkenes in good to excellent yields. This unconventional Heck reaction is proposed to go through initially the formation of a benzylic radical via oxidative addition of the C-N bond with Ni(0), then capturing by aryl alkene via radical addition, followed by single-electron transfer redox and proton abstraction without oxidant and external base.
Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
Lei, Chuanhu,Yip, Yong Jie,Zhou, Jianrong Steve
supporting information, p. 6086 - 6089 (2017/05/08)
Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
TANDEM TRANSFER HYDROGENATION AND OLIGOMERIZATION FOR HYDROCARBON PRODUCTION
-
Paragraph 0125, (2014/07/23)
The disclosure provides for hydrocarbon production by hydrogenation and oligomerizaton and, more particularly, to catalysis of alkanes and alkenes by a tandem transfer hydrogenation and oligomerization.
Scope and mechanism of homogeneous tantalum/iridium tandem catalytic alkane/alkene upgrading using sacrificial hydrogen acceptors
Leitch, David C.,Labinger, Jay A.,Bercaw, John E.
supporting information, p. 3353 - 3365 (2014/08/05)
An in-depth investigation of a dual homogeneous catalyst system for the coupling of alkanes and alkenes based on an early-/late-transition-metal pairing is reported. The system is composed of Cp*TaCl2(alkene) for alkene dimerization and pincer-iridium hydrides for alkane/alkene transfer hydrogenation. Because there is no kinetically relevant interaction between the two catalysts, the tandem mechanism can be entirely described using the two independent catalytic cycles. The alkene dimerization mechanism is characterized by an entropically disfavored pre-equilibrium between Cp*TaCl 2(1-hexene) + 1-hexene and Cp*TaCl 2(metallacyclopentane) (ΔH° = -22(2) kcal/mol; ΔS° = -16(2) eu); thus, the overall rate of alkene dimerization is positive order in 1-hexene (exhibiting saturation kinetics), and increases only modestly with temperature. In contrast, the rate of 1-hexene/n-heptane transfer hydrogenation catalyzed by t-Bu[PCP]IrH4 is inverse order in 1-hexene and increases substantially with temperature. Styrene has been investigated as an alternate sacrificial hydrogen acceptor. Styrene dimerization catalyzed by Cp*TaCl2(alkene) is considerably slower than 1-hexene dimerization. The conversion of styrene/heptane mixtures by the Ta/Ir tandem system leads to three product types: styrene dimers, coupling of styrene and heptane, and heptene dimers (from heptane). Through careful control of reaction conditions, the production of heptene dimers can be favored, with up to 58% overall yield of heptane-derived products and cooperative TONs of up to 12 and 10 for Ta and Ir catalysts, respectively. There is only slight inhibition of Ir-catalyzed styrene/n-heptane transfer hydrogenation under the tandem catalysis conditions.
