Dedicated to Prof. Dieter Seebach on the occasion of his 60th birthday (1 3.11.97) The [Rh,(OAc),]-catalyzed decomposition of {[(4-nitrophenyl)sulfonyl]imino}phenyl-13-iodane (NsN=IPh) resulted in formal insertions into CH bonds, activated by phenyl or vinyl groups, or by 0-substituents. Scope and limitations of the reaction were investigated. Yields of up to 84% were achieved in the most favorable cases. Yields were enhanced by electron-releasing substituents and decreased by steric hindrance. Aziridination competed with allylic insertion with olefinic substrates. The insertion reaction proceeded with retention of configuration. With chiral Rh" catalysts, a modest asymmetric induction was observed. A mechanism involving direct insertion by a Rh-complexed nitrene into the CH bond is proposed.

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The aziridination of olefins with {(4-nitrophenylsulfonyl)imino}phenyl-λ 3 -iodane, NsNTIPh (1c), in the presence of [Rh 2 (OAc) 4 ] proceeds in yields of up to 85% when the olefin is used in large excess. Under optimized conditions, styrene (4a) is aziridinated with 1 equiv. of NsNTIPh (1c) in 64% yield with 2 mol% of catalyst. The aziridines derived from electron-rich olefins undergo ring-opening under the conditions of the aziridination and afford rearrangement products or pyrrolidines. The aziridination is sterospecific with 1,2-dialkyl-and 1,2-arylalkyl-disubstituted olefins, but nonstereospecific with stilbene.The ρ-value for aziridination of substituted styrenes is -0.61. No ring-opened products are observed upon aziridination of vinylcyclopropanes. In the presence of chiral Rh II catalysts, the aziridination is enantioselective, affording an ee of 73% with cis-β-methylstyrene (4k) and Pirrungs [Rh 2 {(R)-(-)-bnp} 4 ] catalyst. The experimental results are consistent with a one-step mechanism for transfer of the nitrenoid moiety from the catalyst to the olefin.