70303-28-5Relevant articles and documents
Highly Stereoselective Positional Isomerization of Styrenes via Acid-Catalyzed Carbocation Mechanism
Hu, Xiao-Si,He, Jun-Xiong,Zhang, Ying,Zhou, Jian,Yu, Jin-Sheng
supporting information, p. 2227 - 2233 (2021/06/28)
The first transition metal-free highly stereoselective positional isomerization of various α-alkyl styrenes through a carbocation mechanism triggered strategy is developed by using Al(OTf)3 as a hidden Br?nsted acid catalyst, which provides facile access to value-added acyclic tri- and tetra-substituted alkenes in good yields with high stereoselectivity under mild conditions. The practicality of this protocol is further highlighted by the gram-scale synthesis, high stereoselectivity, good functional group tolerance, and simple operation. Mechanistic studies support that Al(OTf)3 acts as a hidden Br?nsted acid catalyst and a carbocation intermediate is formed.
Iron-Catalyzed Tunable and Site-Selective Olefin Transposition
Yu, Xiaolong,Zhao, Haonan,Li, Ping,Koh, Ming Joo
supporting information, p. 18223 - 18230 (2020/12/04)
The catalytic isomerization of C-C double bonds is an indispensable chemical transformation used to deliver higher-value analogues and has important utility in the chemical industry. Notwithstanding the advances reported in this field, there is compelling demand for a general catalytic solution that enables precise control of the C═C bond migration position, in both cyclic and acyclic systems, to furnish disubstituted and trisubstituted alkenes. Here, we show that catalytic amounts of an appropriate earth-abundant iron-based complex, a base and a boryl compound, promote efficient and controllable alkene transposition. Mechanistic investigations reveal that these processes likely involve in situ formation of an iron-hydride species which promotes olefin isomerization through sequential olefin insertion/β-hydride elimination. Through this strategy, regiodivergent access to different products from one substrate can be facilitated, isomeric olefin mixtures commonly found in petroleum-derived feedstock can be transformed to a single alkene product, and unsaturated moieties embedded within linear and heterocyclic biologically active entities can be obtained.
Method for stereoselective synthesis of (E)-trisubstituted olefin
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Paragraph 0043-0048; 0100-0102, (2020/04/02)
Belonging to the technical field of metal catalytic synthesis, the invention discloses a method for stereoselective synthesis of (E)-trisubstituted olefin. The method includes: taking 1, 1-disubstituted olefin as the raw material, and adopting a combination of CoX2 and PAO ligand as the catalyst; and in the presence of an activating reagent, carrying out reaction for 0.5min-48h at a temperature ranging from -30DEG C to 80DEG C to prepare (E)-trisubstituted olefin. Compared with the prior art, the method has the advantages of more economical, efficient and environment-friendly catalyst, good tolerance of the reaction functional group, mild reaction conditions, simple operation, no need for participation of additional reagents, and atom economy of 100%. In addition, the reaction has no needof any other toxic transition metal (like ruthenium, rhodium, palladium, etc.) salt, therefore the method has great practical application value in pharmaceutical and food chemical industry.
