In memoriam of Prof. Dr. Tamás Patonay
Abstract
Palladium-catalyzed cross-coupling reactions of polyhalogenated heterocycles provide
a convenient access to multifold arylated and alkynylated ring systems with a broad
spectrum of physical and medicinal properties. Products include thiophenes, selenophenes,
pyrroles, indoles, furans, benzofurans, pyrazoles, pyridines, quinolines, pyrimidines,
pyrazines, naphthyridines, quinoxalines, and others. The regioselectivity of the coupling
reactions is controlled by a combination of electronic and steric parameters. While
a number of couplings can be carried out essentially under standard conditions, others
require the use of more sophisticated ligands and a thorough optimization of the conditions,
such as solvent, temperature, or reaction time. The present Account provides a personalized
overview of coupling reactions of polyhalogenated heterocycles.
1 Introduction
2 Thiophenes
3 Selenophenes
4 Pyrroles and Indoles
5 Furans and Benzofurans
6 Pyrazoles
7 Pyridines
8 Quinolines
9 Pyrimidines and Pyrazines
10 Naphthyridines and Quinoxalines
11 Miscellaneous
12 Conclusions
Keywords
catalysis - cross-coupling - heterocycles - palladium - regioselectivity