3. Ruthenium-Mediated [2 + 2 + 2] Cycloaddition

  1. Ken Tanaka
  1. Yoshihiko Yamamoto

Published Online: 15 JUL 2013

DOI: 10.1002/9781118629871.ch3

Transition-Metal-Mediated Aromatic Ring Construction

Transition-Metal-Mediated Aromatic Ring Construction

How to Cite

Yamamoto, Y. (2013) Ruthenium-Mediated [2 + 2 + 2] Cycloaddition, in Transition-Metal-Mediated Aromatic Ring Construction (ed K. Tanaka), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118629871.ch3

Editor Information

  1. Tokyo University of Agriculture and Technology, Tokyo, Japan

Author Information

  1. Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan

Publication History

  1. Published Online: 15 JUL 2013
  2. Published Print: 15 JUL 2013

ISBN Information

Print ISBN: 9781118148921

Online ISBN: 9781118629871

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Keywords:

  • [2 + 2 + 2] cycloaddition reactions;
  • benzene derivatives;
  • catalysis;
  • cyclotrimerization;
  • heteroaromatics;
  • ruthenium;
  • synthetic applications

Summary

This chapter outlines the advances in the ruthenium-mediated alkyne [2 + 2 + 2] cycloaddition reactions. These can be classified into two major categories in terms of the types of products: syntheses of benzene derivatives via alkyne [2 + 2 + 2] cycloadditions and syntheses of heteroaromatics via [2 + 2 + 2] cycloadditions of alkynes with nitriles or heterocumulenes. Benzene ring—forming reactions are essentially prototypes of the corresponding heteroaromatic annulations. The mechanistic aspects and synthetic applications of ruthenium-catalyzed [2 + 2 + 2] cycloadditions are also described to exemplify the scientific and practical significance of ruthenium catalysis. The reactions that yield benzene rings can be categorized according to the substrates involved: intermolecular cycloaddition of three alkynes (cyclotrimerization), partially intramolecular cycloaddition of diynes with alkynes, and fully intramolecular cyclotrimerization of triynes. Classic examples of [2 + 2 + 2] alkyne cycloadditions using stoichiometric ruthenium mediators are included since they provide useful information on the further development of ruthenium catalysis.