The first example of an asymmetric intramolecular Michaeladdition reaction with use of α-lithiated vinylic sulfoxide as a Michael donor is reported. Michaeladdition of the α-lithiated vinylic sulfoxide to (Z)-enoates proceeds with high diastereoselectivity to give the adducts with (R)-configuration at the β-position of the ester in the five-membered-ring formation. The selectivity was reversed in