The reaction of keto-stabilized sulphonium and arsonium ylides with α-chlorooximes: A new synthesis of Δ2-isoxazolines

Abstract The reaction of α-chlorooximes or the isomeric nitrosochlorides with keto-stabilized dimethylsulphonium or triphenylarsonium ylides affords trans -5-acyl-Δ 2 -isoxazolines (VIIa-m) in good yields. The NOCI adducts of ethylpropenyl ether and ethylstyryl ether on reaction with dimethylsulphonium phenacylide lead directly to the corresponding 3-substituted-5-benzoylisoxazo]es. Dimethylsulphonium carbethoxymethylide on reaction with 2-chloro-2-phenylacetone oxime affords the oxime of β-acetylcinnamic acid ethyl ester, while on reaction with 2-chlorocyclooctanone oxime leads to the thioether IXd.