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Carbohydrates as Chiral Templates: Stereoselective Tandem Mannich‐Michael Reactions for the Synthesis of Piperidine Alkaloids
Author(s) -
Kunz Horst,
Pfrengle Waldemar
Publication year - 1989
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.198910671
Subject(s) - piperidine , diastereomer , stereoselectivity , mannich reaction , chemistry , anabasine , stereochemistry , template , michael reaction , tandem , catalysis , organic chemistry , alkaloid , materials science , composite material , nanotechnology
Pure diastereomers in high yields can be obtained by the reaction sequence shown below followed by crystallization or chromatography. The stereochemical course of the reaction is shown for R = n ‐propyl, p ‐chlorophenyl, and 2‐furyl. Compound 1 , R = 3‐pyridyl, requires two equivalents of ZnCl 2 for catalysis and reacts stereochemically in the opposite fashion. This reaction can be used to obtain enantiomerically pure ( S )‐coniine and ( S )‐anabasine.