Montmorillonite-mediated hetero-Diels–Alder reaction of alkenes and o-quinomethanes generated in situ by dehydration of o-hydroxybenzyl alcohols

The intermolecular hetero-Diels–Alder reaction of in situ-generated o-quinomethanes and unactivated alkenes has been accomplished through a wet montmorillonite catalyst in a LiClO4–MeNO2 solution to give good yields of varied chromane skeletons.