Asymmetric synthesis of substituted prolines by 1,3-dipolar cycloadditionsof azomethine ylides from chiral 6-isopropyl-5-phenylmorpholin-2-ones

Chiral saturated alanine- and glycine-derived 6-isopropyl-5-phenylmorpholin -2-ones 11 and 12 have been prepared and employed for the generation of car boxy-stabilized ylides in asymmetric 1,3-dipolar cycloaddition reactions un der thermal conditions, with electron-deficient dipolarophiles bearing doub le and triple bonds. The cycloadducts are obtained with high stereocontrol and mainly with endo selectivity, and can be used for the synthesis of high ly substituted enantiomerically pure prolines.