Copper-free Sonogashira reaction using 7-chloro camptothecins

We studied copper-free Sonogashira reaction using 7-chloro camptothecins, and determined that rac-BINAP/Pd(OAc)2 was an efficient catalyst for the coupling reaction. With this process, a number of 7-substituted camptothecins with a wide range of functional groups are potentially accessible. Besides, two drugs, SN-38 and BNP-1350, could be prepared by this method.