3. Ruthenium-Mediated [2 + 2 + 2] Cycloaddition
- Ken Tanaka
Published Online: 15 JUL 2013
Copyright © 2013 John Wiley & Sons, Inc. All rights reserved.
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
Tokyo University of Agriculture and Technology, Tokyo, Japan
- Published Online: 15 JUL 2013
- Published Print: 15 JUL 2013
Print ISBN: 9781118148921
Online ISBN: 9781118629871
- [2 + 2 + 2] cycloaddition reactions;
- benzene derivatives;
- synthetic applications
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.