1239700-56-1Relevant articles and documents
Atroposelective Synthesis of Conjugated Diene-Based Axially Chiral Styrenes via Pd(II)-Catalyzed Thioether-Directed Alkenyl C-H Olefination
Jin, Liang,Zhang, Peng,Li, Ya,Yu, Xin,Shi, Bing-Feng
, p. 12335 - 12344 (2021/08/24)
The efficient stereoselective synthesis of conjugated dienes, especially those with axial chirality, remains a great challenge. Herein, we report the highly atroposelective synthesis of axially chiral styrenes with a conjugated 1,3-diene scaffold via a Pd(II)-catalyzed thioether-directed alkenyl C-H olefination strategy. This strategy features easy operation, mild reaction conditions, high functional group tolerance (69 examples), complete Z-selectivity, and excellent enantioselectivities (up to 99% ee). Notably, the highly enantioselective synthesis of atropisomers with two stereogenic axes were also achieved using this strategy (up to 99% ee and 97:3 dr). Moreover, the reaction could be scaled up, and the resulting axially chiral styrenes could be easily oxidized into chiral sulfoxide derivatives with high diastereoselectivities, which showed great promise as a new type of sulfur-olefin ligand.
Copper-catalyzed regioselective hydroboration of terminal alkynes in aqueous medium
Yao, Zi-Jian,Hong, Shibin,Zhang, Wei,Liu, Mengyan,Deng, Wei
supporting information, p. 910 - 913 (2016/02/05)
A mild and environment-friendly copper-catalyzed hydroboration of terminal alkynes in aqueous medium was reported. Regioselectivity control was achieved in the presence of cyclodextrin-bispyridine ligand (CD-1). This protocol was successfully applied to inactivated terminal alkynes. Moreover, the ligand was recovered and reused without any loss of activity over five cycles.
α-Selective Ni-catalyzed hydroalumination of aryl- and alkyl-substituted terminal alkynes: Practical syntheses of internal vinyl aluminums, halides, or boronates
Gao, Fang,Hoveyda, Amir H.
, p. 10961 - 10963 (2010/09/17)
A method for Ni-catalyzed hydroalumination of terminal alkynes, leading to the formation of α-vinylaluminum isomers efficiently (>98% conv in 2-12 h) and with high selectivity (95% to >98% α), is described. Catalytic α-selective hydroalumination reactions proceed in the presence of a reagent (diisobutylaluminum hydride; dibal-H) and 3.0 mol % metal complex (Ni(dppp)Cl2) that are commercially available and inexpensive. Under the same conditions, but with Ni(PPh3)2Cl2, hydroalumination becomes highly β-selective, and, unlike uncatalyzed transformations with dibal-H, generates little or no alkynylaluminum byproducts. All hydrometalation reactions are reliable, operationally simple, and practical and afford an assortment of vinylaluminums that are otherwise not easily accessible. The derived α-vinyl halides and boronates can be synthesized through direct treatment with the appropriate electrophiles [e.g., Br 2 and methoxy(pinacolato)boron, respectively]. Ni-catalyzed hydroaluminations can be performed with as little as 0.1 mol % catalyst and on gram scale with equally high efficiency and selectivity.
