Stitching Oxindoles and Ynones in a Domino Process: Access to Spirooxindoles and Application to a Short Synthesis of Spindomycin B

A general, transition-metal-free, one-pot, domino Michael–SNAr or AdNE substitution protocol was devised for spiroannulation of oxindoles with ortho-bromoaryl ynones, β-bromoalkenyl ynones, and β-bromoalkenyl enones in a convenient and efficient manner. As an application, a short synthesis of tetracyclic alkaloid spindomycin B was accomplished.