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Synlett 2007(12): 1799-1822  
DOI: 10.1055/s-2007-984538
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

Annelated, Chiral π-Conjugated Systems: Tetraphenylenes and Helical β-Oligothiophenes

Andrzej Rajca*a, Suchada Rajcaa, Maren Pinkb, Makoto Miyasakaa
a Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA
b IUMSC, Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
Fax: +1(402)4729402; e-Mail: arajca1@unl.edu;
Further Information

Publication History

Received 2 March 2007
Publication Date:
27 June 2007 (online)

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Abstract

Compounds with highly annelated, chiral π-systems, such as tetraphenylenes and [n]helicenes, are known to possess strong chiral properties and high configurational stability, which are prerequisites for many chiral materials. This account describes the unfolding story about our research on the synthesis and X-ray crystallographic characterization of functionalized nonracemic tetra­phenylenes and helical β-oligothiophenes, as well as related [n]helicene derivatives.

  • 1 Introduction

  • 1.1 Riley’s Three-Dimensional Graphite

  • 1.2 Annelated Helical β-Oligothiophenes: Carbon-Sulfur [n]Helicenes

  • 2 Tetraarylenes

  • 2.1 Double Helical Octaphenylene

  • 2.2 Biphenylene Dimer

  • 2.3 Enantiopure Tetranaphthylene: Binaphthyl Dimer

  • 2.4 Asymmetric Synthesis of Tetraphenylenes: Greek Cross Dodecaphenylene

  • 3 Synthesis of Annelated Helical β-Oligothiophenes

  • 3.1 [7]Helicene

  • 3.2 [7]Helicene: McMurry Reaction

  • 3.3 [11]Helicene

  • 3.4 Toward [n]Helicenes with n >11: Progress Report

  • 4 Discovery of Conjoined Double Helicenes

  • 5 Future Directions

Key words

chirality - asymmetric synthesis - enantiomeric resolution - kinetic resolution - coupling

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65

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The finding of configurational stability for 56 and 56-Li 2 is expected, as less sterically hindered 33-Li 2 is configu-rationally stable as well.

128

Only a preliminary X-ray crystal structure(synchrotron) is available for [9]helicene 60.

129

Unpublished data from Professor Lapkowski’s laboratory (Gliwice, Poland) and from the Rajca laboratory.

135

Rajca, A.; Shiraishi, K.; Pink, M. unpublished research.

139

Functionalized chiral nanotubes and chiral fullerenes may provide molecularly well-defined chiral materials.