This article is affectionately dedicated to Professor Victor Snieckus on the occasion
of his 80th birthday.
Abstract
Convergent routes to a variety of pyrroles involving radical additions of xanthates
are described. Emphasis is placed on reactions leading to the formation of 1,4-diketones
or 1,4-ketoaldehydes or their synthetic equivalents, which can then be condensed with
ammonia or primary amines in a variation of the classical Paal–Knorr synthesis of
pyrroles. The modification of pyrroles by direct radical addition is also discussed.
1 Introduction
2 Earlier Routes to Pyrroles
3 The Xanthate Radical Addition–Transfer Process
4 Application to Pyrrole Synthesis
5 Further Variations
6 Direct Modification of Existing Pyrrole Rings
7 Outlook and Perspectives
Key words
pyrroles - Paal–Knorr reaction - 1,4-diketones - radical addition - xanthates
