Origins of stereoselectivity in the oxido-alkylidenation of alkynes.
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.
Canterbury
Daniel P
DP
Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, USA.
Frontier
Alison J
AJ
Um
Joann M
JM
Cheong
Paul H-Y
PH
Goldfeld
Dahlia A
DA
Huhn
Richard A
RA
Houk
K N
KN
D000478:Alkylation; D000480:Alkynes / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D013237:Stereoisomerism
D000480:Alkynes; D010087:Oxides
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