Enantioselective Synthesis of Spirooxindolopyrrolizidines via Catalytic 1,3-dipolar Cycloaddition of Azomethine Ylides and 3-(2-Alkenoyl)-1,3-oxazolidin-2-ones

摘要

The ability of controlling the selectivity is an important aspect in organic synthesis. Compounds that differ in the position of a substituent are known as regioisomers. Although the regioisomers look very alike, they might possess different properties. Since Padwa and co-workers performed the first diastereoselectivity of 1,3-dipolar cycloaddition reaction in 1985, by applying a chiral non-racemic azomethine ylide, their applications has been developed as a cornerstone in organic synthesis. One of today's challenges in this field is to control the regio-, diastereo- and enantioselectiv-ities of these reactions. Asymmetric 1,3-dipolar cycloaddition reactions of azomethine ylides offer an effective means to access chiral pyrrolidines substructures containing up to four new stereogenic centres that found in many biologically active compounds.3 Asymmetric multicomponent 1,3-dipolar cycloaddition of azomethine ylides with alkenes can be a great interest and useful strategies for stereoselective synthesis and develop of these class of molecules and compounds having similar structure.4 We reported the enantiomerically pure novel spirooxindolpyrrolizidinesby applying optically active cinnamoyloxazolidinone as chiral auxiliary and the enantioselectivities were exceptionally high.