Synthesis 2008(15): 2451-2461  
DOI: 10.1055/s-2008-1067128
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Template-Directed Synthesis of Symmetric as well as Unsymmetric Macrocycles from Rigid or Flexible Building Blocks

Markus Albrecht*, Yeni
Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
Fax: +49(241)8092385; e-Mail: markus.albrecht@oc.rwth-aachen.de;
Further Information

Publication History

Received 31 March 2008
Publication Date:
11 June 2008 (online)

Abstract

‘Arc’-shaped oligophenyl derivatives with terminal alkene moieties can be used to form macrocycles by ‘dimerization’ through ring-closing metathesis. Hereby the introduction of templates connecting the two building blocks favors the dimerization over oligomerization or polymerization reactions. Attachment of the template through imine formation allows the removal of the template simultaneous to the reduction of the double bonds formed during ring-closing metathesis. Unsymmetric macrocyles can be obtained either­ by successive attachment of different ‘arc’-shaped molecules to the template or by direct imine connection of two different ring precursors. In the latter case, the imine unit cannot be cleaved in the case of the investigated examples but ‘figure-8’-shaped macrobicycles are obtained. The studied template-directed macrocyclization depends on the one hand on the preorganization of the building blocks, and on the other on their flexibility.