N-Pyridylmethylephedrine derivatives in the catalytic asymmetric addition of diethylzinc to aldehydes and diphenylphosphinoylimines

Article abstract of DOI:10.1016/j.tetasy.2009.08.014

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.