title: Enantioselective Conversion of Achiral Cyclohexadienones to Chiral Cyclohexenones by Desymmetrization.
abstract: The enantioselective reduction of prochiral 4,4-disubstituted 2,5-cyclohexadienones to chiral 2-cyclohexenones has been accomplished by the use of a carefully selected chiral bisphosphine-CuI complex and diisobutylaluminum hydride-hexamethylphosphoric triamide complex. This reagent has provided access to a key bicyclic intermediate for the total synthesis of the natural enantiomer of the pentacyclic sesterterpene retigeranic acid that involves spatial discrimination between CH3and CH2CH2R substituents, an operation that has been elusive previously. In addition, a second method for desymmetrization is described using catalytic enantioselective [4 + 2]-cycloaddition of cyclopentadiene to prochiral 4,4-disubstituted 2,5-cyclohexadienones.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Simon
authors.initials: S
authors.lastname: Breitler
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Shao-Liang
authors.initials: SL
authors.lastname: Zheng
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: E J
authors.initials: EJ
authors.lastname: Corey