... RSC Adv., 2013, 3, 7697-7703 ... Received 9th January 2013 , Accepted 15th March 2013. ... Stahl 9 and Myers 10 have reported the use of Sc(OTf) 3 , Al 2 (NMe 2 ) 6 , and Ti(NMe 2 ) 4 complexes as homogeneous catalysts which work under mild reaction conditions. ...