A modular route to highly substituted pyrroles has been developed. This transformation consists of two sequential copper-catalyzed vinylations of bis-Boc-hydrazine followed by thermal rearrangement/cyclization. A wide variety of functionalized pyrroles can be prepared in a selective manner from simple and easily accessible precursors.
“Copper-Catalyzed Vinylation of Hydrazides. A Regioselective Entry to Highly Substituted Pyrroles”, Org. Lett., 2007, 9(6), 973-976.