- A concise synthesis of (R)-(+)-phenylalaninol from (1S,2S)-(+)- thiomicamine
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(R)-(+)-Phenylalaninol 6 was obtained from oxazolines 3 and 4 derived from (1S,2S)-2-amino-1-aryl-1,3-propanediols 1 and 2 by the action of Raney nickel followed by hydrolysis of the intermediate benzamide 5.
- Rozwadowska, Maria D.
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p. 1615 - 1618
(2007/10/03)
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- New homochiral bis(oxazoline) ligands for asymmetric catalysis
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Several homochiral bis(oxazolines), with asymmetric centers on the oxazoline rings and on the side chains, were prepared from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol in high yields. Asymmetric cyclopropanation of styrene with ethyl diazoacetate in th
- Hoarau,Ait-Haddou,Castro,Balavoine
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p. 3755 - 3764
(2007/10/03)
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- Diastereoselective conversion of sulfides into sulfoxides. 1,5- and 1,6-asymmetric induction
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The diastereoselective oxidation of sulfides into sulfoxides has been achieved with enantiomerically pure dihydrooxazole auxiliaries. When an additional hydroxymethyl substituent is present, diastereocontrol is very high and 1,5-asymmetric induction has been achieved with up to 96:4 selectivity, and 1,6-asymmetric induction has been achieved with up to 97:3 selectivity in the absence of any additional chiral agents.
- Bower, Justin F.,Martin, Christopher J.,Rawson, David J.,Slawin, Alexandra M. Z.,Williams, Jonathan M. J.
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p. 333 - 342
(2007/10/03)
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- Enantiomerically pure oxazolines tethered to alcohols. Preparation and use in asymmetric catalysis
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A series of enantiomerically pure oxazolines tethered to alcohols have been prepared. The use of these oxazolines has been demonstrated in the catalysed addition of diethylzine to aromatic aldehydes to afford the corresponding secondary alcohols with modest levels of asymmetric induction.
- Allen,Williams
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p. 277 - 282
(2007/10/02)
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- 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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p. 1237 - 1254
(2007/10/02)
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