Stereoselective Route to 2,3,4,5-Tetraaryltetrahydrofurans via Efficient Cascade Synthesis of 2,3-Dihydrofurans with Four Different (Hetero)Aryl Substituents

Tf₂NH-mediated regio- and diastereoselective skeletal metamorphosis of 1-alkynyl-2,3-diaryl-2-methoxycarbonylcyclopropyl ketones readily gave 2,3,4,5-tetraaryl-2,3-dihydrofurans. Controllable reduction and removal of the ester group then precisely afforded four types of the eight possible tetrahydrofuran (THF) diastereomers with four different (hetero)aryl substituents. Further, deuterium-labeling results revealed an unprecedented hydrogen transfer from the formyl C–H bond in ^tBuOK-promoted decarbonylation under ^tBuOH-free conditions.