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DOI: 10.1055/s-0029-1219327
Rational Design of Diels-Alder Catalysts
A. Sakakura, R. Kondo, Y. Matsumura, M. Akakura, K. Ishihara*
Nagoya University and Aichi University of Education, Kariya, Japan
Publication History
Publication Date:
18 February 2010 (online)
Significance
Non-coordinating anions are widely used in cationic catalysts for Diels-Alder reactions to enhance the reactivity. However, the use of labile cationic catalysts is often accompanied with side reactions, product inhibition, and catalyst decomposition. In this paper the authors suggest a way to overcome these issues by the use of weak secondary interactions to stabilize the cationic species. Thus, heteroatoms Y can displace counterions X, leading to equilibrium between species A and B. In order to avoid the equilibrium, protic HZ moieties can be used to displace counterions with their subsequent stabilization. This approach proved to be highly efficient in system 1: NHMs groups were dramatically superior to the analogues with OMe and OAc substituents. The proposed interaction picture was supported by theoretical calculations.