title: Stereoselectivity in Oxyallyl-Furan 4+3 Cycloadditions: Control of Intermediate Conformations and Dispersive Stabilisation with Evans' Oxazolidinones.
abstract: Chiral oxazolidinones were previously thought to control cycloaddition stereoselectivity by steric crowding of one face of the substrate. We have discovered that in 4+3 cycloaddition reactions of oxallyls, the stereoinduction is caused instead by stabilising CH-π interactions that lead to reaction at the more crowded face of the oxazolidinone. Density functional theory calculations on the 4+3 cycloadditions of oxazolidinone-substituted oxyallyls with furans establish unexpected transition state conformations and a new explanation of selectivity.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Krenske
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Lohse
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Antoline
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hsung