An Enantioselective Approach to Furanoeremophilanes: (+)‑9‑Oxoeuryopsin

An
enantioselective total synthesis of the furanoeremophilane sesquiterpene
(+)-9-oxoeuryopsin 1 is reported. The synthesis involves
as a key step a copper­(II) triflate catalyzed tandem asymmetric conjugate
addition of AlMe3 to 2-methyl-2-cyclohexen-1-one with the
Feringa (S,R,R)-phosphoramidite
binaphthol ligand, followed by aldol condensation of the resulting
aluminum enolate with 4-methyl-3-furaldehyde 4. This
tandem transformation has not been previously reported with a 2-substituted-2-cyclohexen-1-one.
Conventional functional group manipulations completed the synthesis.