Synthesis 2006(22): 3805-3808  
DOI: 10.1055/s-2006-950299
PAPER
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Syntheses of 3,4-Substituted Tetrahydroquinoline Derivatives by (-)-Sparteine-Mediated Dynamic Thermodynamic Resolution of 2-(α-Lithiobenzyl)-N-pivaloylaniline

Yongtae Kima, Eun-kyoung Shina, Peter Beakb, Yong Sun Park*a
a Department of Chemistry and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea
Fax: +82(2)34365382; e-Mail: parkyong@konkuk.ac.kr;
b Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
Weitere Informationen

Publikationsverlauf

Received 19 May 2006
Publikationsdatum:
09. Oktober 2006 (online)

Abstract

(-)-Sparteine-mediated dynamic thermodynamic resolution of 2-(α-lithiobenzyl)-N-pivaloylaniline was investigated. A temperature- and concentration-controlled epimerization-substitution sequence provides a simple protocol for the preparation of a highly enantioenriched benzyl-substituted N-pivaloylaniline product (up to 98:2 er). Also, application of this simple methodology to asymmetric syntheses of 1,3,4- and 3,4-substituted tetrahydroquinoline derivatives is demonstrated.

5

Reaction of 2-(1-lithioethyl)-N-pivaloylaniline with tert-butyl bromoacetate under the same reaction conditions gave the substituted product in lower enantioselectivity (84:16 er) and yield (22%).