Catalytic, selective, and stereocontrolled construction of C4 quaternary and homobenzylic dihydroisoquinolones by sp3 C–H benzylation

Abstract

C1 benzylated isoquinoline derivatives constitute the core of benzylisoquinoline alkaloids (BIAs). However, their C4 congeners remain elusive. Here, we describe a diastereoselective, catalytic, and modular C(sp³)–C(sp³) coupling protocol wherein β-amino sp³ C–H bonds of readily affordable vicinally functionalized dihydroisoquinolones are replaced by sp³ C–benzyl bonds. The method provides expedient access to C4 quaternary and homobenzylic dihydroisoquinolones, which are attractive fragments for potential drug discovery.