Asymmetric Synthesis of (S)-Mirtazapine: Unexpected Racemization through an Aromaticipso-Attack Mechanism
作者:Marco van der Linden、Judith Borsboom、Frans Kaspersen、Gerjan Kemperman
DOI:10.1002/ejoc.200701224
日期:2008.6
An asymmetricsynthesis of (S)-mirtazapine has been achieved from the synthesis of the racemate by using (S)-1-methyl-3-phenylpiperazine as the starting material. Unfortunately, significant racemization was encountered in the final step, which involved an electrophilic aromatic ring closure of a alcohol by concentrated sulfuric acid. A significantly higher ee was observed when polyphosphoric acid (PPA)