Comparison of the reactivity between 2- and 3-nitropyrroles in cycloaddition reactions. A simple indole synthesis

N-Tosyl-2-nitropyrroles react at high temperature with poorly and strongly activated dienes. They exhibit a dienophilic character similar to N-tosyl-3-nitropyrroles producing the corresponding indoles through a classical Diels Alder process. A similar behaviour was observed in disubstituted N-tosyl-pyrroles. (c) 2006 Elsevier Ltd. All rights reserved.