Abstract
This review article features selected examples on the synthesis of functionalized
pyrroles that were reported between 2014 and 2019. Pyrrole is an important nitrogen-containing
aromatic heterocycle that can be found in numerous compounds of biological and material
significance. Given its vast importance, pyrrole continues to be an attractive target
for the development of new synthetic reactions. The contents of this article are organized
by the starting materials, which can be broadly classified into four different types:
substrates bearing π-systems, substrates bearing carbonyl and other polar groups,
and substrates bearing heterocyclic motifs. Brief discussions on plausible reaction
mechanisms for most transformations are also presented.
1 Introduction
2 From π-Systems
2.1 Alkenes
2.2 1,6-Dienes
2.3 Allenes
2.4 Alkynes
2.5 Propargylic Groups
2.6 Homopropargylic Amines
3 From Carbonyl Compounds
3.1 Aldehydes
3.2 Ketones
3.3 Cyanides and Isocyanides
3.4 Formamides
3.5 β-Enamines
3.6 Dicarbonyl Compounds
4 From Polar Compounds
4.1 Aminols
4.2 Diols
4.3 Organonitro Compounds
5 From Heterocycles
5.1 Münchnones
5.2 Isoxazoles
5.3 Carbohydrates
5.4 trans-4-Hydroxy-l-prolines
5.5 Pyrrolines
6 Summary
Key words
pyrroles - heterocycles - carbonyls - annulation - aromatic
