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2-Methyleneaziridines can be tethered to a variety of alkene or alkyne acceptors through the saturated carbon of the heterocyclic ring by application of a simple lithiation/alkylation sequence (8 examples, 31-59%). Treatment of the resultant alkene bearing substrates with BF(3)·OEt(2) leads to cis-octahydrocyclopenta[c]pyrroles in which up to four contiguous stereocentres are created in a diastereocontrolled manner after reductive work-up. Using an alkyne based substrate, a 2,4,5,6-tetrahydrocyclopenta[c]pyrrole is produced by rapid tautomerisation of the initially formed bisenamine. Evidence that these (3 + 2) 'cycloadditions' proceed in a stepwise manner via a 2-aminoallyl cation is presented.

Treatment of nitriles with an organometallic reagent followed by a mixture of KCN and ammonium carbonate provides a synthesis of diversely 5,5-disubstituted hydantoins. -(MONTAGNE, C.; SHIPMAN*, M.; Synlett 2006, 14, 2203-2206; Dep. Chem., Univ. Warwick, Coventry CV4 7AL, UK; Eng.) -Mais 50-139