932-66-1Relevant articles and documents
“Release and Catch” Effect of Perfluoroalkylsulfonylimide-Functionalized Imidazole/Pyridine on Br?nsted Acids in Organic Systems
You, Li,Ren, Xiao-Fei,Wang, Yun,Ma, Zhong-Hua,Gu, Yanlong,Ma, Jing-Zhong
, p. 3394 - 3401 (2016)
A “release and catch” method was developed by utilising the scavenging effect of a fluorous zwitterion on a homogeneous triflic acid (TfOH) catalyst in Michael addition and Rupe rearrangement. Both TfOH and the zwitterion were recycled with >90 % recovery using toluene. The zwitterions were designed by functionalising imidazole/pyridine with the perfluoroalkylsulfonylimide group. The “caught” TfOH was delivered to ethyl acetate and re-used. The smooth delivery was primarily because of the fluorous tail of the zwitterion, the hydrophobicity of which probably weakened the ability of the zwitterion to form H bonds, so that retro-ion-exchange occurred towards the formation of the acid and zwitterion. The method was universal for other strong Br?nsted acids such as H2SO4 and p-MeC6H4SO3H. The method combined the significant advantages of homogeneous catalysis and heterogeneous isolation. Based on the H0 acidity function and the 31P NMR chemical shift of Et3P=O adducts, it is reasonable to deduce that the decrease of the acid strength of the formed composites of Br?nsted acids and the zwitterion drove the scavenging effect.
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Nasarow et al.
, (1956)
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Access to Cycloalkeno[ c]-Fused Pyridines via Pd-Catalyzed C(sp2)-H Activation and Cyclization of N-Acetyl Hydrazones of Acylcycloalkenes with Vinyl Azides
Nie, Biao,Wu, Wanqing,Ren, Qingyun,Wang, Zhongqing,Zhang, Ji,Zhang, Yingjun,Jiang, Huanfeng
supporting information, p. 7786 - 7790 (2020/11/02)
A novel Pd(II)-catalyzed vinylic C-H activation and cyclization has been developed, reacting a series of small, medium, and large N-acetyl hydrazones of acylcycloalkenes with vinyl azides to access diverse cycloalkeno[c]-fused pyridine scaffolds. This protocol provides progress in C(sp2)-H bond activation of medium to large cycloalkenes, and the target products can be obtained in a specific regioselectivity with good functional group tolerance and a broad substrate scope.
Balancing Bulkiness in Gold(I) Phosphino-triazole Catalysis
Zhao, Yiming,Wakeling, Matthew G.,Meloni, Fernanda,Sum, Tze Jing,van Nguyen, Huy,Buckley, Benjamin R.,Davies, Paul W.,Fossey, John S.
, p. 5540 - 5548 (2019/08/07)
The syntheses of a series of 1-phenyl-5-phosphino 1,2,3-triazoles are disclosed, within which, the phosphorus atom (at the 5-position of a triazole) is appended by one, two or three triazole motifs, and the valency of the phosphorus(III) atom is completed by two, one or zero ancillary (phenyl or cyclohexyl) groups respectively. This series of phosphines was compared with tricyclohexylphosphine and triphenylphosphine to study the effect of increasing the number of triazoles appended to the central phosphorus atom from zero to three triazoles. Gold(I) chloride complexes of the synthesised ligands were prepared and analysed by techniques including single-crystal X-ray diffraction structure determination. Gold(I) complexes were also prepared from 1-(2,6-dimethoxy)-phenyl-5-dicyclohexyl-phosphino 1,2,3-triazole and 1-(2,6-dimethoxy)-phenyl-5-diphenyl-phosphino 1,2,3-triazole ligands. The crystal structures thus obtained were examined using the SambVca (2.0) web tool and percentage buried volumes determined. The effectiveness of these gold(I) chloride complexes to serve as precatalysts for alkyne hydration were assessed. Furthermore, the regioselectivity of hydration of but-1-yne-1,4-diyldibenzene was probed.
