Investigation of site selectivity of the stereoselective deprotonation of cyclohexene oxide using kinetic resolution of isotopic enantiomers in natural abundance
2005 (English)In: Tetrahedron-Asymmetry, Vol. 16, no 15, 2665-2671 p.Article in journal (Refereed) Published
Stereo selective deprotonation of epoxides with lithium arnides can occur by abstraction of protons from more than one site. The site selectivity of the deprotonation of cyclohexene oxide by several chiral and achiral lithium amides has been investigated. H-2 NMR has been used to measure the relative abundances of the isotopomers of the epoxide containing one deuterium. An isotopic stereoisomer, with deuterium in the site undergoing abstraction, reacts slower than its enantiomer and other isotopomers having protium in the same site due to a kinetic isotope effect. This results in a kinetic resolution yielding a relative excess of the less reactive isotopic stereoisomer. Thus, the relative abundance of such an enantiomer increases when compared with those having protium at the site in question as the reaction proceeds. It can be concluded that deprotonation of cyclohexene oxide using some chiral- and non-chiral lithium amides occurs by beta syn-deprotonation. (c) 2005 Elsevier Ltd. All rights reserved.
Place, publisher, year, edition, pages
2005. Vol. 16, no 15, 2665-2671 p.
IdentifiersURN: urn:nbn:se:uu:diva-137510DOI: 10.1016/j.tetasy.2005.06.029OAI: oai:DiVA.org:uu-137510DiVA: diva2:378396