Copper-catalyzed addition of organometallic reagents to vinyl diepoxides- A novel route to oxa-bridged systems and to substituted allylic alcohols

The copper-catalysed addition of organometallic reagents (Grignard and dialkylzinc) to new vinyl diepoxides was examined. Cyclic vinyl diepoxides undergo clean S(N)2' reactions to afford oxa-bridged systems of various sizes after a domino intramolecular O-alkylation reaction. Acyclic vinyl diepoxides are alkylated in good yields and with good regioselectivities, and a new catalytic enantioselective desymmetrization reaction to afford an enantioenriched allylic epoxy alcohol by the use of catalytic amounts of a copper phosphoramidite complex was demonstrated. Remarkable differences in terms of reactivity and selectivity are found when different organocopper reagents, generated in situ, are employed.