26227-06-5Relevant academic research and scientific papers
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.
Construction of C-C Bond via C-N and C-O Cleavage
He, Rong-De,Pang, Xiaobo,Shu, Xing-Zhong
, p. 635 - 640 (2020/04/07)
The construction of a C-C bond is a center subject in synthetic organic chemistry. The cross-electrophile coupling has provided a powerful tool to forge the C-C bond. However, this process generally requires organic halides, which has severely restricted
Oxidative cross-coupling of allyl(trimethyl)silanes with aryl boronic acids by palladium catalysis
Zhou, Zhibing,Hou, Zhen-Lin,Yang, Fan,Yao, Bo
, p. 7228 - 7236 (2018/11/03)
The first oxidative cross-coupling of allylsilanes with aryl boronic acids has been developed by palladium catalysis. The reaction between β-substituted allyl(trimethyl)silanes and a wide range of aryl boronic acids afforded allylarenes in moderate to good yields and excellent selectivity. On the basis of experimental results and literature reports, it was suggested that the reaction might start from transmetalation of aryl boronic acid with AgOAc followed by transmetalation with Pd(II) to give an arylpalladium acetate complex as a key intermediate. This intermediate underwent either electrophilic addition/desilylation or transmetalation with allylsilane and subsequent reductive elimination to give the final product.
Pd-catalyzed ligand-free Suzuki reaction of β-substituted allylic halides with arylboronic acids in water
Dong, Chaonan,Zhang, Lingjuan,Xue, Xiao,Li, Huanrong,Yu, Zhiyong,Tang, Weijun,Xu, Lijin
, p. 11152 - 11158 (2014/03/21)
The catalyst system consisting of Pd(TFA)2 and KOH allows for a wide range of β-substituted allylic halides to react efficiently with various arylboronic acids in neat water under ligand-free conditions, affording the allylated arenes in high yields with broad functional group tolerance and up to 7.4 × 105 TON and 15416 h-1 TOF.
