85858-12-4Relevant articles and documents
On the Stereoselectivity of Epoxide Formation using Dimethyloxosulphonium Methylide. X-Ray Structure of (5SR)-5-pyrrolidin-2-one
Fray, M. Jonathan,Thomas, Eric J.,Wallis, John D.
, p. 395 - 402 (2007/10/02)
As background to a proposed dendrobatid toxin 251 D synthesis, the stereoselectivity of epoxide formation from 5-acetylpyrrolidin-2-one (4) and dimethyloxosulphonium methylide was investigated.In THF under 'salt-free' conditions, the major epoxide product, selectivity 78:22, was (5SR)-5-pyrrolidin-2-one (5), whereas addition of anhydrous ZnCl2 to the reaction mixture reversed the stereoselectivity to give epoxides (5) and (6) in the ratio 23:77.Configurations were assigned to these epoxides by comparison of n.m.r. spectra of the derived carbamates (15) and (16), and by an X-ray structure determination for epoxide (6).Related reactions are discussed.
