Asymmetric synthesis of multicyclic spiro-1,3-indandiones via a cascade Michael/Michael reaction of curcumins and 2-arylidene-1,3-indandiones

An organocatalytic cascade Michael/Michael reaction between curcumins and 2-arylidene-1,3-indandiones has been studied. Prolinol, chiral thiourea-tertiary amines, and cinchona alkaloids were evaluated as catalysts. Quinine was identified as the best catalyst for the transformation. Multicyclic spiro-1,3-indandiones were prepared in moderate to excellent yields, diastereoselectivities, and enantioselectivities.