Efficient syntheses of enantioenriched (R)-pipecolic acid and (R)-proline via electrophilic organocatalytic amination
作者:Delphine Kalch、Nicolas De Rycke、Xavier Moreau、Christine Greck
DOI:10.1016/j.tetlet.2008.11.054
日期:2009.1
Five-step syntheses of (R)-pipecolic acid and (R)-proline are described, respectively, from cyclohexene and cyclopentene. The key step involves the ganocatalytic alpha-amination of functionalized aldehydes. (C) 2008 Elsevier Ltd. All rights reserved.
Organocatalytic asymmetric syntheses of functionalized tetrahydropyridazines
作者:Delphine Kalch、Ramzi Ait Youcef、Xavier Moreau、Christine Thomassigny、Christine Greck
DOI:10.1016/j.tetasy.2010.07.030
日期:2010.9
Four tetrahydropyridazines, respectively, substituted at the C-3 position with hydroxymethyl, a silyloxymethyl, a carboxylic acid, and a methyl ester have been prepared in good yields and high enantiomeric purities using organocatalytic alpha-amination of aldehydes as the key step. These compounds have then been tested as organocatalysts for the same reaction. (C) 2010 Elsevier Ltd. All rights reserved.
Asymmetric α-Amination of Aldehydes and Ketones Catalyzed by tert-Butoxy-L-Proline
Asymmetric electrophilic α-amination of aldehydes and ketones is described using trans-3-tert-butoxy-Lproline and trans-4-tert-butoxy-L-proline as efficient catalysts. Good yields and high enantioselectivities are obtained working at 0°C or at room temperature with a catalyst loading of only 5 mol%.