Synlett 2017; 28(09): 1018-1027
DOI: 10.1055/s-0036-1588153
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© Georg Thieme Verlag Stuttgart · New York

Thieme Chemistry Journals Awardees – Where Are They Now? Aromaticity as a Source for Strain Energy? Synthesis of Curved Polycyclic Aromatic Structures via [2+2+2] Cycloaddition Reactions

Sebastian Beeck
Justus-Liebig-Universität Gießen, Institut für Organische Chemie, Heinrich-Buff-Ring 17, D-35392 Gießen, Germany   Email: Hermann.A.Wegner@org.Chemie.uni-giessen.de
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Hermann A. Wegner*
Justus-Liebig-Universität Gießen, Institut für Organische Chemie, Heinrich-Buff-Ring 17, D-35392 Gießen, Germany   Email: Hermann.A.Wegner@org.Chemie.uni-giessen.de
› Author Affiliations
Further Information

Publication History

Received: 11 January 2017

Accepted after revision: 15 February 2017

Publication Date:
08 March 2017 (online)


Abstract

This account describes synthetic approaches for curved polycyclic aromatics such as circulenes, helicenes and cycloparaphenylenes, relying on a [2+2+2] cycloaddition. A common feature of all these structures is that their synthesis needs to deviate benzene rings from planarity. Relying on [2+2+2] cycloaddition reactions for this task leads to impressive, and in parts, surprising results. The examples shown here and their optimized reaction conditions contribute to a better understanding of processes going on during the reaction. This knowledge is expected to lead to new designs of challenging syntheses using the [2+2+2] cycloaddition methodology.

1 No Gain, No Strain: Synthesis of Curved Aromatics

2 Examples for the Preparation of Strained Systems Relying on a [2+2+2] Cycloaddition

2.1 Circulenes

2.2 Helicenes

2.3 Cycloparaphenylenes

3 Conclusion and Outlook