Functional Ionic Liquids Promoted Double Michael Reaction of Benzofuran-3-one or 1-Indone and Symmetric Dienones: Construction of Spiro[benzofuran-2,1'-cyclohexane]-3-one or Spiro[cyclohexane-1,2'-indene]-1',4(3'H)-dione Derivatives

The double Michael reactions between benzofuran-3-one or 1-indone and symmetric dienones in the presence of catalytic ionic liquids were successfully developed and spiro[benzofuran-2,1'-cyclohexane]-3-one or spiro[cyclohexane-1,2'-indene]-1',4(3'H)-dione derivatives containing a spiro quaternary stereogenic center, which widely exist in biologically active products and building blocks in organic synthesis, were obtained in excellent yields (up to 99%). This catalytic system was also extended to the double Michael reaction of less reactive 1-indone and the desired products were also obtained in 31%-62% yields. The catalytic system was highly active and efficient for a broad of substrates under mild conditions.