Novel Cinchona alkaloid derived ammonium salts as catalysts for the asymmetric synthesis of beta-hydroxy alpha-amino acids via aldol reactions.
Using the cinchonidine-derived phase-transfer catalyst de veloped by Park and Jew as a lead structure, we have prepared novel chiral ammonium salts and investigated their efficacy for the preparation of beta-hydroxy alpha-amino acids via asymmetric aldol reactions. The modifications were performed at C3 of the cinchonidine nucleus and include dimers as well as catalysts possessing electron-deficient alkyne and alkene moieties. Some of the new catalysts yielded improvements relative to the Park-Jew catalyst in the aldol reaction.
Ma
Bing
B
Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
Parkinson
Jared L
JL
Castle
Steven L
SL