Pyrrole Synthesis

This pyrrole synthesis published by Barry Trost and co-workers looks very practical with low catalyst loadings (0.75-1.5 mol % palladium acetate (PdOAc)2 and TDMPP (tris-(2,6-dimethoxyphenyl)phosphine) followed by 2-5 mol % Pd(OTFA)2, palladium trifluoroacetate) and mild conditions (toluene, room temperature).

If the Pd(OTFA)2 is not added the enyne intermediate can be isolated.  Indeed if the enyne product is reacted with a Pd catalyst and an alkene such as allyl chloride or acrolein, 2,3,4-trisubstituted pyrroles can be produced.

B.M. Trost,* J.-P. Lumb, and J.M. Azzarelli, J. Am. Chem. Soc., 2011, 133, 740-743.