Efficient and convenient copper-free Pd(OAc)2/Ruphos-catalyzed Sonogashira coupling in the preparation of corfin analogues

The Sonogashira coupling reaction of 3-chloro-1H-isochromen-1-one and terminal alkynes, in the presence of catalytic system-Pd(OAc)2/Ruphos, Et3N base, and tetrahydrofuran solvent under aqueous conditions, provided novel 3-(alkynyl)-1H-isochromen-1-ones in excellent yields. The methodology has also been extended toward natural isochromen-1-ones-corfin analogues.