chiral induction in cycloaddition reactions of azomethine ylides to synthesis of new enantiomerically pure spiro oxindolopyrrolizidines

an efficient one-pot three-component procedure for the synthesis of new chiral spiro-oxindolopyrrolizidines with highly regio-, diastereo-, and enantioselective from 1,3-dipolar cycloaddition of azomethine ylides and optically pure active cinamoyl oxazolidinone are described. the process occurs at room temperature in aqueous ethanol as green solvent and in the absence of any bidentate chelating lewis acids. the oxazolidinone chiral auxiliary has been attached to the dipolarophile and removed from the cycloadducts in a non-destructive method. the mechanism of the reaction is discussed on the basis of the assignment of the absolute configuration of one of the cycloaddition products, which obtained by x-ray single crystal structure analysis, and theoretical calculations.