Molecular hybridization-guided annulation reactions of isatins with 4-methylpent-3-en-2-one: A direct access to spirooxindole tetrahydropyranones

An efficient molecular hybridization strategy has been utilized for the synthesis of pirooxindole tetrahydropyranones 3 through annulation reactions of isatins 1 with 4-methylpent-3-en-2-one 2. Products consist of a pirooxindole tetrahydropyranone scaffold and propan-2-ether unit were smoothly obtained in moderate yields (up to 56% yield). The one-pot, two-step reaction, avoiding the isolation and purification of intermediates C, has proved to be a practical protocol. This protocol leads to new knowledge in the fields of both molecular complexity and the lead compound discovery.