Ru-Catalyzed Carbonylative Murai Reaction: Directed C3-Acylation of Biomass-Derived 2-Formyl Heteroaromatics
We describe here the carbonylative Murai reaction applied to 2-formylfurans, 2-formylpyrrols and 2-formylthiophenes. Thanks to the installation of removable imine directing groups, this acylation reaction takes place regioselectively at C3 position of the heterocyclopentadienes. It can be achieved by treating the two reaction partners with a catalytic amount of Ru3(CO)12, in toluene at 120-150 °C, after CO bubbling, at atmospheric pressure. DFT computations of the full catalytic cycle help in deciphering the mechanism of this transformation, and to rationalize the different behaviors depending on the nature of imine directing groups.