- Enantioselective Cyclopropanation of 1,1-Diphenylethylene and Diazoacetic Acid Ester with Copper Catalysts
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Copper(II) compounds catalyze the reaction of 1,1-diphenylethylene with diazoacetic acid ethylester.The main product is 2,2-diphenylcyclopropane carboxylic acid ethylester.The formation of the carbene dimerization products fumaric and maleic acid diethylester can be suppressed by the continuous addition of diazoacetic ester to 1,1-diphenylethylene. 37 optically active ligands, partly new, were combined with copper(II)-acetate to give in-situ-catalysts.In five cases isolated copper complexes were used as catalysts.The best optical inductions in the formation of 2,2-diphenylcyclopropane carboxylic acid ethylester with up to 65.6percent ee were achived with Schiffbase ligands, which derive from salicylaldehyde and amino alcohols, obtained from amino acid esters and phenyl Grignard. - Keywords: Catalytic enantioselective cyclopropanation; Copper(II) catalysts; Optical induction.
- Brunner, Henri,Miehling, Wolfgang
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- X-Ray Structure and Force Field Calculations of a Chiral Benzaldehyde Schiff Base
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The crystal structure of the Schiff base formed from benzaldehyde and (R)-2-aminobutan-1-ol is compared to one obtained from force-field calculations employing a new parameter set; the probable structure of the hydrogen-bonded Schiff base dimer is discuss
- Heuser, Norbert,Klein, Michael,Messinger, Josef,Buss, Volker,Raabe, Eleonore,Krueger, Carl
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- Derivatives of (R) and (S)-2-amino-1-butanol as possible anti-arrhythmics
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The chiral imines derived from (R) and (S)-2-amino-1-butanol have been reported.Some of the chiral imines have been found to be in equilibrium with the corresponding 1,3-oxazolidines, which on treatment with sodium borohydride in methanol are reduced to the corresponding N-benzyl derivatives.
- Kumar, G. Biju,Shah, A. C.
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