Tandem One-Pot Synthesis of 2H- and 3H-Pyrroles Enabled by Dual Rh(II)/Pd(0) Catalysis

Regioselective approaches toward 2H- and 3H-pyrroles, which are biologically important but easily isomerizable compounds, have been successfully achieved via dual Rh(II)/Pd(0) relay catalysis and DBU-mediated processes in one-pot operation using N-tosyltriazoles and hydroxymethylallyl carbonates. In this transformation, readily accessible N-tosyltriazoles were enabled as stable nitrogen sources for the two scaffolds, and the regioselectivity was controlled by the substituent positions of the hydroxymethylallyl carbonates.