A new asymmetric domino sulfa-Michael/aldol reaction of 2-arylidene-1,3-indandiones with 1,4-dithiane-2,5-diol catalyzed by a sub-mol% loading of a squaramide provides a direct access to tetrahydrothiophene bearing spiro indane-1,3-dione derivatives in excellent yields and good stereoselectivities.