title: Origins of stereoselectivity in the oxido-alkylidenation of alkynes.
abstract: A mild, convenient oxido-alkylidenation of alkynes is described. The three-step sequence involves the 1,3-dipolar cycloaddition of a nitrone and an alkynoate, oxidation of the resulting isoxazoline, and stereoselective extrusion of nitrosomethane. Quantum mechanical calculations identified the interactions of R3 with the oxidant and the preferred conformation of a diradical intermediate as major factors controlling the stereoselectivity of the oxidation and torquoselectivity of the extrusion.
authors.affiliation: Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Canterbury
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Frontier
authors.forename: Joann M
authors.initials: JM
authors.lastname: Um
authors.forename: Paul H-Y
authors.initials: PH
authors.lastname: Cheong
authors.forename: Dahlia A
authors.initials: DA
authors.lastname: Goldfeld
authors.forename: Richard A
authors.initials: RA
authors.lastname: Huhn
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
mesh_terms: D000478:Alkylation; D000480:Alkynes / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D010087:Oxides
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