Unusual stereo- and chemo-selective photocyclization of chiral α-aminoacid-incorporated 2-acyl benzamides by control of chiral memory

An unusual decarboxylative photocyclization of 2-acyl benzamides with intramolecular chiral α-aminoacids was studied. The reaction exclusively yields bi- and tri-cyclic benzo-oxazepines via distinct chemoselective C-O bond formation. High enantio- and diastereo-selectivities (ee = 87-99% and dr = 85/15-95/5) for the products were achieved. Evidence indicates that the formation of the two chiral carbon centers is controlled by chiral memory.