One-Pot Method Produces Pyrroles

A new synthetic method simplifies the production of 2,4-disubstituted pyrrole heterocycles—an important class of structures common in the chemistry of natural products and pharmaceuticals. Barry M. Trost and colleagues at Stanford University have been developing one-pot reactions of substituted alkynes to create important organic building blocks—an efficient strategy that maximizes atom economy. In this most recent case, Trost’s group, which includes Jean-Philip Lumb and Joseph M. Azzarelli, describes the synthesis of a number of 2,4-disubstituted pyrroles (shown), which were prepared from various substituted aromatic alkynes in the presence of a palladium catalyst (J. Am. Chem. Soc., DOI: 10.1021/ja110117g). The process is tolerant to moisture and air and can be carried out at room temperature. The authors also report that intermediates produced during the reaction can be captured and further functionalized to species such as 2,3,4-trisubstituted pyrroles and 3-substituted pyrrolidin-2-ones.