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[reaction: see text] Enantiomerically enriched beta-(diphenylphosphatoxy)nitroalkanes undergo radical ionic fragmentation, induced by tributyltin hydride and AIBN in benzene at reflux, to give alkene radical cations in contact radical ion pairs. These contact ion pairs are trapped intramolecularly by amines to give pyrrolidines and piperidines with significant enantioselectivity ( approximately 60% ee), indicative of cyclization competing effectively with equilibration within the ion pairs. Use of an intramolecular N-propargylamine as a nucleophile provides an enantiomerically enriched pyrrolizidine skeleton via a tandem polar/radical crossover sequence.

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It is demonstrated that alpha,alpha-disubstituted-alpha-nitroketones are reduced to the corresponding trisubstituted nitro alcohols in good to excellent yield and enantiomeric excess by borane-dimethyl sulfide in the presence of a chiral oxazaborolidine catalyst. Reduction of the nitro alcohols to the corresponding amino alcohols and their subsequent conversion to enantiomerically enriched 4,4,5-trisubstituted oxazoldinones is also reported.

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