Synthesis of chiral spiro 3-oxazolin-5-one 3-oxides (Chiral nitrones) via a nitrosoketene intermediate and their asymmetric 1,3-dipolar cycloaddition reactions leading to the EPC synthesis of modified amino acids,

Article abstract of DOI:10.1016/S0040-4020(97)00284-6

Cycloaddition of chiral cyclic ketones such as (-)-menthone, (+)-nopinone, and (+)-camphenilone to nitrosokelene generated by thermolysis of 5-hydroxyimino-2,2-dimethyl-1,3-dioxane-4,6 dione gave the corresponding chiral spiro 3-oxazolin-5-one 3-oxides (chiral cyclic nitrones). These nitrones underwent asymmetric 1,3-dipolar cycloddition reactions with electron rich olefins to give the corresponding oxazolidine derivatives with high diastereoselectivity, which were converted to optically pure amino acids.