Synthesis of N-H-Free 1,4-Dihydroisoquinoline-3(2H)-ones via Pd-Catalyzed C-H Olefination Using Polyfluorosulfinyl as the Auxiliary Group

A Pd(II)-catalyzed olefination of aryl C-H bonds with a self-cleaving 2-chlorotretafluoroethylsulfinyl (-SOCF2CF2Cl) auxiliary was developed. In the reaction mixture, the olefination products underwent in situ Michael addition and the subsequent expulsion of the auxiliary to provide the N-H-free 1,4-dihydroisoquinoline-3(2H)-one products. Mechanistic studies reveal that the auxiliary group is crucial for C-H activation, and Na2CO3 and an alcoholic solvent play key roles in facilitating the cleavage of the polyfluoroalkylsulfinyl auxiliary.