230635-32-2Relevant academic research and scientific papers
Synthesis of an Enantiomerically Pure Inherently Chiral Calix[4]Arene Phosphonic Acid and Its Evaluation as an Organocatalyst
Karpus, Andrii,Yesypenko, Oleksandr,Boiko, Vyacheslav,Daran, Jean-Claude,Voitenko, Zoia,Kalchenko, Vitaly,Manoury, Eric
, p. 1146 - 1153 (2018)
A facile method for the preparation of enantiomerically pure inherently chiral calix[4]arene phosphonic acid (cR,pR)-7 in four steps starting from the readily available and previously synthesized (cS)-enantiomer of calix[4]arene acetic acid 1 or its methyl ester 2 was developed. The first tests of this unique calixarene Br?nsted acid with inherent chirality in organocatalysis of the aza-Diels-Alder reaction of imines with Danishefsky's diene and epoxide ring opening by benzoic acid were performed. The calixarene phosphonic acid (cR,pR)-7 shows good catalytic activities but with low enantioselectivities in these reactions.
Chiral catalyst optimization using both solid-phase and liquid-phase methods in asymmetric aza Diels-Alder reactions
Kobayashi, Shu,Kusakabe, Ken-Ichi,Ishitani, Haruro
, p. 1225 - 1227 (2000)
(Equation presented) In the presence of 1-5 mol % of a chiral zirconium catalyst, aza Diels-Alder reactions of aldimines with Danishefsky's dienes proceeded smoothly to afford the corresponding piperidine derivatives in high yields with high enantioselect
Niobium-catalyzed highly enantioselective aza-diels-alder reactions
Jur?ík, Václav,Arai, Kenzo,Salter, Matthew M.,Yamashita, Yasuhiro,Kobayashi, Shu
supporting information; experimental part, p. 647 - 651 (2009/04/21)
Niobium-based chiral Lewis acid was found to be highly effective catalyst for aza-Diels-Alder reactions of imines with Danishefsky's dienes. The reactions proceed in high yield with high enantioselectivity for both aromatic and aliphatic imines. The developed methodology was applied to total synthesis of (+)-anabasine.
ASYMMETRIC-SYNTHESIS CATALYST BASED ON CHIRAL BROENSTED ACID AND METHOD OF ASYMMETRIC SYNTHESIS WITH THE CATALYST
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Page/Page column 45-46, (2010/11/08)
A compound usable as an asymmetric synthesis catalyst which can be easily synthesized without using any metal such as a lanthanoid group element; a method of asymmetric synthesis with the compound; and a chiral compound obtained by the asymmetric synthesis method. A Broensted acid is used as a catalyst in asymmetric synthesis, the chiral Broensted acid being represented by formula (1) below or formula (3) below. The asymmetric synthesis method employs the catalyst. Asymmetric synthesis with the catalyst gives a chiral compound.
