77036-87-4Relevant academic research and scientific papers
Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C-H Activation
Di Monaco, Sabrina,Pang, Benjamin Piaoxiang,Rahman, Md. Shafiqur,Thai, Anh Ngoc,Wang, Chang-Sheng,Wang, Chen,Yoshikai, Naohiko
supporting information, p. 12878 - 12889 (2020/08/21)
A catalytic system comprising a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines and related azines, imidazo[1,2-a]pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic systems for analogous transformations, the present catalytic systems not only feature convenient setup using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp) but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Meanwhile, the present catalytic system proved to promote exclusively C5-selective alkenylation of imidazo[1,2-a]pyridine derivatives. Mechanistic studies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkenyl(carbamoyl)cobalt intermediate.
Controllable assembly of the benzothiazole framework using a CC triple bond as a one-carbon synthon
Huang, Yubing,Yan, Donghao,Wang, Xu,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 1742 - 1745 (2018/02/21)
A concise and efficient protocol to assemble diverse benzothiazole derivatives in high yields was provided via copper catalyzed tandem cyclization with o-haloanilines, elemental sulfur and terminal alkynes as raw materials. In this protocol, C atoms on the CC triple bond were controllably involved in the construction of the benzothiazole framework and multiple carbon-heteroatom bonds through divergent routes.
GAS/SOLID-REACTIONS WITH SULFUR COMPOUNDS
Kaupp, Gerd,Luebben, Doris,Sauerland, Olaf
, p. 109 - 120 (2007/10/02)
The various types of gas/solid-reactions (addition, elimination, substitution, condensation, catalyzed cycloaddition) in different branches of sulfur chemistry (heterocycles, S-vinyl-compounds, thioethers, thiols, sulfur dioxide) are reviewed, new types a
Multifunctional Photoadditions of Stilbene to Derivatives of Caffeine and Benzothiazole
Kaupp, Gerd,Ringer, Ernst
, p. 1525 - 1539 (2007/10/02)
Electronically excited stilbene (1*) is trapped by 8-substituted caffeine derivatives (2a-f) or 2-chloro- (14) and 2-aminobenzothiazole (21) with variable results.While the electron-rich systems (2c,d) produce mostly propellanes, the halogeno compounds 2a,b and 14 react predominantly via insertion into the C-halogen bond.With 14 there occurs also some C-S insertion, with 21 only N-H insertion.Numerous succeeding reactions are elucidated and the reaction mechanisms discussed.Stilbene (1) photoadds hydrogen chloride to yield 16.
-Eliminations and -Substitutions of a Bicyclic β-Lactone Dithioacetal
Kaupp, Gerd
, p. 4271 - 4275 (2007/10/02)
Photolytic, thermal, and acid-catalyzed -eliminations of methanethiol from the benzobicyclic β-lactone dithioaqcetal 1 to form the benzothiazole derivatives 4 and 5 are investigated.Competing reactions are -substitutions, which ultimately yield 2-benzylbenzothiazole (6) and benzaldehyde.Intermediate 7 is isolated upon careful hydrolysis.These reactions are compared to -eliminations from the 1,5-benzothiazepine 9 and to its -rearrangement to give 10. 9 and 10 are not intermediates in the reactions of 1.The stereochemistry of 7 and 10 is discussed.
Thermal -Elimination of Methanethiol from a 1,5-Benzothiazepine Derivative
Kaupp, Gerd
, p. 1643 - 1646 (2007/10/02)
Upon heating to 200 deg C, the 1,5-benzothiazepine derivative 1 eliminates methanethiol to form the benzothiazole derivative 2, but not the 1,5-benzothiazepine 5.The structure of 2 is established by independent synthesis from 3, photolysis to give 4, and spectroscopic data.The reaction of 1 to give 2 and methanethiol is termed a -elimination.
ZUR REAKTIONSWEISE DES 3-ETHOXY-1,2-DIPHENYL-CYCLOPROPENYLIUMKATIONS MIT BIFUNKTIONELLEN AROMATISCHEN AMINEN
Eicher, Theophil,Lerch, Dieter
, p. 3751 - 3754 (2007/10/02)
The reaction of 3-ethoxy-1,2-diphenyl cyclopropenylium cation with bifunctional aromatic amines is described, which gives rise to benzazoles in an unexpected expansion mode of the cyclopropenone system.
