Synthesis 2002(3): 0381-0392
DOI: 10.1055/s-2002-20040
PAPER
© Georg Thieme Verlag Stuttgart · New York

Stereoselective Intermolecular Carbolithiation of Open-Chain and Cyclic 1-Aryl-1-alkenyl N,N-Diisopropylcarbamates Coupled with Electrophilic Substitution. Observation of p-Carboxylation in a Benzyllithium Derivative

Jan Georg Peters, Michael Seppi, Roland Fröhlich, Birgit Wibbeling, Dieter Hoppe*
Institut für Organische Chemie der Westfälischen Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
Fax: +49(251)8339772; e-Mail: dhoppe@uni-muenster.de;
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Publication History

Received 8 November 2001
Publication Date:
28 July 2004 (online)

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Abstract

1-Aryl-1-alkenyl N,N-diisopropylcarbamates (1) are obtained from alkyl aryl ketones and N,N-diisopropylcarbamoyl chloride (CbCl) by heating with excess pyridine. These undergo facile syn-carbolithiation by alkyllithium/diamine and produce configurationally stable lithiated benzyl carbamates, which have been trapped with different electrophiles. If the reaction is carried out in the presence of chiral diamines, such as (-)-sparteine or (-)-α-isosparteine, moderate enantiofacial differentiation is observed.