MMT/FeCl3-catalyzed Friedel-Crafts Alkylation of Ethyl 2-(bis(ethylthio)methylene)-3-hydroxybutanoate with Indole Derivatives

An inexpensive and environmentally friendly MMT/FeCl3 catalyzed Friedel-Crafts alkylation of α-hydroxy ketene dithioacetals with indole derivatives has been developed.The reaction was efficiently performed in the presence of MMT/FeCl3(15mol%) at room temperature in CH2Cl2,affording α-indolyl ketene dithioacetals in excellent yields.The procedure was characterized by lower amount of inexpensive catalyst,mild reaction condition,environmentally benign and simplicity.