On the origin of altered diastereomeric ratios for anionic versus neutral reaction conditions in the oxy-Cope/ene reaction: an interplay of experiment and computational modeling.
We report herein a detailed investigation into the reaction mechanism for a sequential oxy-Cope/ene reaction under anionic conditions. With DFT calculations and ab initio molecular dynamics simulations, the observed diastereoselectivity is shown to be the result of an isomerization of the enolate olefin, which would evidently not occur under neutral conditions. The potential energy surface was thoroughly mapped out for the reaction pathways and the proposed mechanism confirmed the different product distributions observed under neutral and anionic oxy-Cope conditions. In addition, other possible pathways are shown to be higher in energy and experimental evidence is given that supports the olefin-isomerization pathway.
Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, K1N 6N5 ON, Canada.
James
J
Hooper
Effiette L O
EL
Sauer
Steve
S
Arns
Tom K
TK
Woo
Louis
L
Barriault
D000475:Alkenes / Q000737:chemistry*; D000838:Anions / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004987:Ethers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D013237:Stereoisomerism
D000475:Alkenes; D000838:Anions; D004987:Ethers