Regiodivergent Resolution of Unsymmetrical Oxabicyclic Alkenes

Significance

The Lautens group reports a rare example of a regiodivergent resolution of bridgehead-substituted oxabenzonorbornene derivatives under rhodium catalysis. From earlier work, these oxabicycles were shown to undergo [Rh(CO)₂Cl]₂-catalyzed addition of methanol to provide product type A based on complete substrate control. However, when these substrates were treated with a chiral rhodium complex, two regioisomers (type A and B) resulting from Rh insertion into either C-O bond were obtained each in excellent enantioselectivity. Subsequently, various oxabi­cycles and alcohol- and amine-based nucleophiles could be used under these reaction conditions.