157367-55-0Relevant 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.
Photoinduced Electron Transfer (PET) cyclization and photooxygenation of 2,6-diaryl-1,6-heptadienes and 2,7-diaryl-1,7-octadienes
Griesbeck, Axel G.,Sadlek, Oliver,Polborn, Kurt
, p. 545 - 549 (2007/10/03)
The 2,6-diaryl-substituted 1,6-heptadienes 3a-c and the 2,7-diaryl-substituted 1,7-octadienes 4a-b were cleanly converted into the corresponding anellated cyclobutanes 5 and 6, resp., when irradiated under photoelectron-transfer conditions (9,10-dicyanoanthracene in acetonitrile). Only for 4c did the rearranged compound 7c become the dominant photoproduct. Oxygen trapping experiments with formation of endoperoxides 8, 9 were successful in the case of the electron-rich substrates 3b, c and 4c. VCH Verlagsgesellschaft mbH, 1996.
