Sulfoxide-directed thermal intramolecular [4 + 2] cycloadditions between 2-sulfinyl butadienes and unactivated alkynes

2-Sulfinyl butadienes tethered to unactivated alkynes undergo a facile thermal Aintramolecular Diels–lder cycloaddition, often at room temperature, to produce cyclohexa-1,4-dienes with good selectivities, in high yields, and preserving the valuable vinyl sulfoxide functionality.