Recent Synthetic Methods for Pyrroles and Pyrrolenines (2H- or 3H-Pyrroles)

Abstract

The methods employed in the synthesis of monocyclic pyrroles and pyrrolenines (2H- and 3H-pyrroles) have been surveyed. The procedures have been classified according to the type of precursor used (cyclic or acyclic) in the production of the pyrrole system. 1. Pyrroles from Cyclic Precursors 1.1. Ring Substitution Reactions 1.2. Substituent Alteration Reactions 1.3. Elimination Reactions 1.4. Rearrangement Reactions 1.5. Ring Expansion Reactions 1.6. Ring Contraction Reactions 2. Pyrroles from Acyclic Precursors 2.1. Mucic Acid 2.2. Dicarbonyl Compounds 2.3. Acyloins 2.4. Unsaturated Compounds 2.5. Azines 2.6. Enamines 2.7. Amino Carbonyl Compounds or Precursors (Knorr Method) 2.8. Halo Carbonyl Compounds 3. Pyrrolenine (2H- and 3H-Pyrrole) Syntheses 3.1. Alkylation Methods 3.2. lsomerization Methods 3.3. Ring Closure Methods 3.4. Oxidative Methods 3.5. Miscellaneous Methods