Copper catalysed asymmetric ring opening reaction of oxabenzonorbornadienes with grignard and aluminium reaggents

A highly enantioselective method for the copper-catalyzed desymmetrization of oxabenzonorbornadienes with aluminum reagents and SimplePhos as chiral ligand has been developed. The same reaction with Grignard reagents is also reported. A wide range of alkyl chains have been used with moderate to high enantio­selectivity and high trans selectivity. The transfer of a methyl group is also reported with high enantiomeric and diastereomeric excess and yields for different substrates. We finally have been able to perform the first trans enantioselective desymmetrization of oxabenzonorbornadienes with an aromatic group