A Solvent-Induced Reversal of Regioselectivity in the Suzuki Coupling of Pyrrole Esters

Abstract

During a study of the regioselectivity of the Suzuki coupling of dihalopyrrole esters, the first instance of a re- versal of regioselectivity based upon a change in reaction solvent has been observed. It is believed that this change in re- gioselectivity is due to a change in solvation of the pyrrole ester, since a change in chemical shift values is observed for the C3 and C5 protons upon going from DMF to chloroform to 3:1 benzene/methanol. An attempted application of this regioselectivity to the synthesis of the lamellarin family of natural products is reported as well.