Radical Fluorosulfonylation/Double Diels-Alder Sequence to Access Tricyclo[3.2.1.02,7]octanes.

A cascade strategy for the rapid construction of tricyclo[3.2.1.02,7]octanes is reported. This one-pot, two-step sequence can be efficiently accomplished by utilizing readily available propargylic alcohols as the starting materials and FSO2Cl as the fluorosulfonyl radical precursor. The FSO2-functionalized tricyclooctane products, bearing multiple reactive sites, are poised for postderivatizations. Based on mechanism studies, a cascade sequence involving radical hydro-fluorosulfonylation, dehydration, and a double Diels-Alder reaction has been proposed.