摘要:
N-Pyridylmethyl-substituted Ephedra derivatives were synthesized by either direct alkylation or reductive alkylation of (1R,2S)-norephedrine, (1S,2S)-pseudo norephedrine, and (1R,2S)-ephedrine. These derivatives were then employed in asymmetric addition reactions with diethylzinc and aldehydes and diphenylphosphinoylimines. The use of the diastereomers from the Ephedra family allowed for a systematic evaluation of the contribution of the N-pyridylmethyl. (C) 2009 Elsevier Ltd. All rights reserved.