Synthesis of Enantiopure Spiro-isoxazolidine from stable Ketonitrones via [۳+۲] Cycloaddition in High pressure condition

Because of enantiopure spiro-isoxazolidine importance, an efficient system was advanced for them synthesis through an asymmetric ۱, ۳-dipolar cycloaddition reaction of N-Phenyl Acenaphthylen/Oxindole Nitrones and an optically active ۱, ۳-dipolarophile equipped with chiral auxiliary. The best result in diastereoselectivity was obtained by use of (S)-Oxazolidinone as chiral auxiliary. After the extensive investigations to find the best conditions for increasing the reactivity of stable keto-nitrones, it was found that in high-pressure condition, a favorable reactivity is obtained. Further, in order to improve the efficiency of the reaction, more active dipolarophile was synthesized and chiral spiro-isoxazolidine were synthesis in the high yield.

Keywords:

enantiopure spiro-isoxazolidine , asymmetric ۱ , ۳-dipolar cycloaddition reaction , N-Phenyl Acenaphthylen/Oxindole Nitrones , chiral auxiliary , high-pressure condition.