Synthesis 2004(18): 2980-2990  
DOI: 10.1055/s-2004-834861
PAPER
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Synthesis of 3-Substituted Dihydro-2H-isoquinolin-1-ones, Dihydro- and Tetrahydroisoquinolines via 1,2-Addition/Ring Closure

Dieter Enders*, Volker Braig, Marine Boudou, Gerhard Raabe
Institut für Organische Chemie, Rheinisch-Westfälische Technische Hochschule, Professor-Pirlet-Straße 1, 52 074 Aachen, Germany
Fax: +49(241)8092127; e-Mail: Enders@rwth-aachen.de;
Further Information

Publication History

Received 16 August 2004
Publication Date:
07 October 2004 (online)

Abstract

The asymmetric synthesis of 3-substituted dihydro-2H-isoquinolin-1-ones, dihydro- and tetrahydroisoquinolines is described. The key operation is a tandem 1,2-addition/ring closure sequence employing lithiated ortho-toluamides and aldehyde SAMP- or RAMP-hydrazones as substrates, followed by N-N bond cleavage to remove the auxiliary. Moderate to good yields and high enantiomeric excesses (ee = 85-99%) are reached.

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The crystal structure of (R)-5a has been deposited as supplementary publication no. CCDC-236862 at the Cambridge Crystallographic Data Centre. Copies of the data can be obtained free of charge on application to CCDC 12 Union Road Cambridge CB2 1EZ UK (fax: +44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or http//www.ccdc.cam.ac.uk).