Rhodium-catalyzed asymmetric ring opening of oxabicyclic alkenes with phenols

[GRAPHICS] The scope of the rhodium-catalyzed asymmetric ring opening reaction of oxabenzonorbornadiene has been extended to include phenolic nucleophiles. The enanatioenriched, functionalized dihydronaphthalene products are highly valuable intermediates for which no other practical methods of preparation are available. A new catalyst system has been developed which allows the use of less reactive o-halophenols. The utility of these products has been demonstrated through their application in the synthesis of benzofuran polycyclic materials.