Diastereoselectivity and Reactivity in the Diels‐Alder Reactions of α‐Chloronitroso Ethers

摘要: The structure of the α-chloronitroso ether 1, obtained from hydroximolactone 2 and tert-butyl hypochlorite (89%), was established by X-ray crystallographic analysis. [4 + 2] cycloadditions 1 with dienes 3 8–11 led to N-unsubstituted 3,6-dihydro-2H-1,2-oxazines 6 12–16 in high enantiomeric excess (Table 1). Due additional α-alkoxy group, reactivity is much superior one known α-chloronitrosoalkanes. reactive conformation deduced analysis as well diastereoselectivity cycloadditions. importance group evidenced similar racemic ethers 25–27 which were prepared hydroximo 28–30 hypochlorite.