Enantioselective synthesis of 2,2,5-tri- and 2,2,5,5-tetrasubstituted tetrahydrofurans via [4 + 2] cycloaddition and ring-opening cross-metathesis.

A chiral vinyl sulfoxide has been developed that undergoes highly diastereoselective Diels-Alder cycloadditions with various substituted furans in excellent yield. The cycloadducts can be stereoselectively transformed into 2,2,5-tri- and 2,2,5,5-tetrasubstituted tetrahydrofurans, which are structural subunits of many natural products, via regioselective ring-opening metathesis/cross-metathesis or oxidative cleavage/refunctionalization.