Synthesis of Hydroxylated Polycyclic Pyrrolo/Indolo[1,2-<i>a</i>]quinoxaline-Fused Lactam Derivatives via PhI(OAc)₂-Promoted 1,2-Bond Migration and Solvent Insertion

PhI(OAc)2-mediated ring expansion via 1,2-bond migration and concurrent solvent insertion generate hydroxylated polycyclic pyrrolo/indolo[1,2-a]quinoxaline-fused lactam derivatives in a highly diastereoselective fashion from spiro-fused quinoxalines in good-to-excellent yield. X-ray crystal structure analysis reveals that the polycyclic lactams are nonplanar molecules devoid of any symmetry as they possess one or two axially chiral biaryl or N-arylindolyl bridges along with one chiral center at the bridgehead carbon.