We report a new process to access highly enantioenriched sulfur-based heterocycles by an asymmetric catalytic thio-Diels-Alder reaction. Thiocarbonyls are challenging heterodienophiles in enantioselective Diels-Alderreactions, due to their inherent high reactivity and their poor ability to coordinate to chiral catalysts. We successfully circumvented these problems by employing a different strategy