Enantioselective Synthesis of Spiro[1,3-indanedione-tetrahydrothiophene]s by Organocatalytic Sulfa-Michael/Michael Domino Reaction

The organocatalytic asymmetric domino reaction between 2-arylidene-1,3-indanediones and 4-mercapto-2-butenoates for the construction of chiral spiro[indane-1,3-dione-tetra-hydrothiophene] skeletons was developed. In the presence of a tertiary amine-thiourea organocatalyst, a series of 2-arylidene- 1,3-indanediones reacted with tert-butyl 4-mercapto-2-butenoate smoothly to furnish chiral spiro heterocycles in good yields (75-99%) with high enantioselectivities (89-99% ee) and diastereoselectivities (75.4:24.6 to 97.1:2.9dr). Notably, functionalized chiral spiro heterocycles were also built in one pot through an aldol condensation/sulfa-Michael/ Michael domino reaction in similarly high yields with high asymmetric induction.