| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 99 === Since last few years, our group has been focusing on the design and synthesis of pyrrolidinyl-camphor derived organocatalysts for the asymmetric reactions. These novel pyrrolidinyl-camphor derived organocatalysts have proven to be very effective in asymmetric synthesis. Kinetic resolution is one of the conventional methods to obtain enantiomerically enriched compounds from racemic mixtures. Herein, we have developed pyrrolidinyl-camphor derived organocatalysts for the kinetic resolution of nitroallylic acetates (derived from the Baylis-Hillman reaction) via conjugate addition-elimination reaction using ketones as a donor.
In the beginning, we have employed pyrrolidinyl-camphor derivatives (116, 119-123, 139) in the reaction of cylcohexanone 19 to nitroallylic acetate 133 via conjugate addition-elimination pathway. After extensive optimization studies, the reaction was carried out in MTBE at 0 oC, in the presence of 20 mol% of organocatalyst 139. The densely functionalized product 138c was obtained with high chemical yield (40%) and excellent enantioselectivity (94% ee), and the acetate 133c was recovered with moderate chemical yield (35%) and good enantioselectivity (89% ee).
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