Pyrrolidines, synthesis from oximes

As discussed in Chapter 6, nitro compounds are converted into amines, oximes, or carbonyl compounds. They serve as usefid starting materials for the preparation of various heterocyclic compounds. Especially, five-membered nitrogen heterocycles, such as pyrroles, indoles, ind pyrrolidines, are frequently prepared from nitro compounds. Syntheses of heterocyclic compounds using nitro compounds are described partially in Chapters 4, 6 and 9. This chapter focuses on synthesis of hetero-aromadcs fmainly pyrroles ind indolesi ind saturated nitrogen heterocycles such as pyrrolidines ind their derivadves. 

The chiral moiety of the nitrone can also be located at the carbon atom. Yokoyama et al. [50] used this approach in the asymmetric synthesis of spiro isoxazohdines (Scheme 10.21). The ribose-derived nitrone 62 is obtained from the corresponding oxime by Michael addition to methyl acrylate. With a second equivalent of methyl acrylate, the sugar nitrone 62 gave a single cycloadduct 63, which was converted into the corresponding pyrrolidine by reduction. 

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