228546-60-9Relevant academic research and scientific papers
Chemical On/Off Switching of Mechanically Planar Chirality and Chiral Anion Recognition in a [2]Rotaxane Molecular Shuttle
Corra, Stefano,De Vet, Christiaan,Groppi, Jessica,La Rosa, Marcello,Silvi, Serena,Baroncini, Massimo,Credi, Alberto
, p. 9129 - 9133 (2019)
We exploit a reversible acid-base triggered molecular shuttling process to switch an appropriately designed rotaxane between prochiral and mechanically planar chiral forms. The mechanically planar enantiomers and their interconversion, arising from ring shuttling, have been characterized by NMR spectroscopy. We also show that the supramolecular interaction of the positively charged rotaxane with optically active anions causes an imbalance in the population of the two enantiomeric coconformations. This result represents an unprecedented example of chiral molecular recognition and can disclose innovative approaches to enantioselective sensing and catalysis.
Triphenylphosphonium-stoppered [2]rotaxanes
Rowan, Stuart J.,Cantrill, Stuart J.,Stoddart, J. Fraser
, p. 129 - 132 (1999)
(equation presented) The template-directed syntheses of two [2]rotaxanes, one carrying one and the other two triphenylphosphonium stoppers, have been achieved using a threading-followed-by-stoppering approach. Either one or two benzylic bromide functions-
Rotaxane formation under thermodynamic control
Cantrill, Stuart J.,Rowan, Stuart J.,Stoddart, J. Fraser
, p. 1363 - 1366 (1999)
Thermodynamic control operates in the synthesis of a [2]rotaxane based upon the dibenzylammonium ion/crown ether recognition motif. When dibenzo[24]crown-8 is added to an acetonitrile solution containing a diimine dumbbell-like component, the dynamic natu
Continuous hydrogenation reactions in a tube reactor packed with Pd/C
Yoswathananont, Nungruethai,Nitta, Kohei,Nishiuchi, Yumi,Sato, Masaaki
, p. 40 - 42 (2005)
Continuous flow of the substrate solution and hydrogen gas through a tube reactor packed with Pd/C catalyst brings about a highly reactive and efficient hydrogenation system, which converts 4-cyanobenzaldehyde to the benzyl alcohol derivatives at 25 °C, and at 90 °C, the cyano group becomes reduced to give the corresponding amine and toluene derivatives within 2 min.
Switching Selectivity in Copper-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amine-Boranes and Secondary Amines under Mild Conditions
Guo, Liangcheng,Song, Hao,Wang, Ren,Xiao, Yao,Xiong, Wanjin,Zhang, Zhuohua,Zhou, Taigang
, (2022/01/11)
A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine-BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
Selective Synthesis of Secondary Amines from Nitriles by a User-Friendly Cobalt Catalyst
Sharma, Dipesh M.,Punji, Benudhar
supporting information, p. 3930 - 3936 (2019/07/12)
Selective hydrogenation/reductive amination of nitriles to secondary amines catalyzed by an inexpensive and user-friendly cobalt complex, (Xantphos)CoCl2, is reported. The use of (Xantphos)CoCl2 and ammonia borane (NH3?BH3) combination affords the selective reduction of nitriles to symmetrical secondary amines, whereas the employment of (Xantphos)CoCl2 and dimethylamine borane (Me2NH?BH3) along with external amines produce unsymmetrical secondary amines and tertiary amines. The general applicability of this methodology is demonstrated by the synthesis of 43 symmetrical and unsymmetrical secondary and tertiary amines bearing diverse functionalities. (Figure presented.).
Directed one-pot syntheses of crown ether wheel-containing main chain-type polyrotaxanes with controlled rotaxanation ratios
Nakazono, Kazuko,Ishino, Tomonori,Takashima, Tomoyuki,Saeki, Daisaku,Natsui, Daisuke,Kihara, Nobuhiro,Takata, Toshikazu
supporting information, p. 15341 - 15344 (2015/02/19)
The directed synthesis of main chain-type polyrotaxanes possessing crown ether wheels was successfully achieved through two methods, A and B. Method A involved the direct wheel threading of poly(sec-ammonium salt) followed by end-capping with a bulky group, while method B utilized polyaddition of a pseudo[2]rotaxane monomer to facilitate the control of the structure, i.e. the rotaxanation ratio.
