A series of synthetically interesting 2-arylbenzoxazinones was prepared from 2-arylindoles
by an efficient oxidative reaction mediated by (diacetoxyiodo)benzene [PhI(OAc)2] and assisted by water. PhI(OAc)2 was used as the sole oxidant and water was a crucial additive. Our preliminary mechanistic
investigations suggest that a water-involved, iodine(III)-promoted sequential oxidation
of 2-arylindoles, which was terminated by an interesting Grob-type fragmentation of
a fused tricyclic precursor, might be the main components of this one-pot transformation.
Key words
benzoxazinones - hypervalent iodine - indoles - oxidation - water-assisted