Rapid construction of S-containing spirooxindoles and dispirooxindoles via annulation of MBH maleimides of isatins

Abstract

The novel S-containing spirooxindoles and dispirooxindoles were conveniently synthesized from the annulation reaction of MBH maleimides with S-containing nucleophiles. The annulation reaction of pyridinium 1,4-zwitterionic thiolates and MBH maleimides of isatins in refluxing chloroform afforded functionalized spiro[indoline-3,4′-thiopyrano[2,3-c]pyrroles] in satisfactory yields. On the other hand, DMAP promoted annulation reaction of elemental sulfur and MBH maleimides of isatins in refluxing acetonitrile resulted in functionalized dispiro[indoline-3,8′-thiepino[2,3-c:6,7-c’]dipyrrole-9′,3′’-indolines] in high yields and with high diastereoselectivity. The relative configuration of the dispirooxindoles was confirmed by determining of the single crystal structure.