119244-11-0Relevant articles and documents
Unexpected metal base-dependent inversion of the enantioselectivity in the asymmetric synthesis of α-amino acids using phase-transfer catalysts derived from cinchonidine
Mazon, Patricia,Chinchilla, Rafael,Najera, Carmen,Guillena, Gabriela,Kreiter, Rob,Klein Gebbink, Robertus J.M.,Van Koten, Gerard
, p. 2181 - 2185 (2002)
New cinchonidinium salts bearing a 3,5-dialkoxybenzyl group show an alkaline metal base-dependent reversal of enantioselectivity when used as phase-transfer catalysts in the asymmetric alkylation of N-(diphenylmethylene)glycine isopropyl ester with benzyl bromide. The use of potassium hydroxide as base in this alkylation reaction afforded the (S)-enantiomer, whereas using sodium hydroxide under the same conditions afforded the corresponding (R)-enantiomer.
Oxygen alkylation of Schiff base derivatives of amino acids
O'Donnell,Cook,Rusterholz
, p. 989 - 993 (2007/10/02)
Higher imine esters 1a-h and 7a-b of amino acids and dipeptides are prepared in 68-91% yield by saponification of the benzophenone Schiff base methyl esters 3a-d and 6 using phase-transfer techniques followed by O-alkylation with an alkyl halide. The procedure occurs with retention of configuration at the α-carbon except with phenylglycine derivatives.
