Synergistic [4 + 1] Spiroannulation and Selective Ring-Opening Strategy toward γ-Spirolactams

A unique and propitious [4 + 1] spiroannulation of 2-aryl-4<i>H</i>-benzo[<i>d</i>][1,3]oxazine with maleimide has been delineated, furnishing diversely embellished γ-spirolactams featuring pendant benzyl alcohol via Rh(III)-catalyzed consecutive ring closing/ring opening followed by regioselective cleavage of the C4-O bond of 1,3-benzoxazine promoted by an <i>in situ</i> generated water maneuver constructing new C-C, C-N, and C-O bonds at a go. A detailed mechanistic study, including a thorough analysis of the incorporation of an extra oxygen source, has been showcased to make this strategy for structurally orchestrated isoindoline-1-one spirosuccinimides.