The mechanism of the copper-catalyzed aziridination of alkenes using [N-(p-toluenesulfonyl)imino]phenyliodinane (PhINTs) as the nitrene source has been elucidated by a combination of hybrid density functional theory calculations (B3LYP) and kinetic experiments. The calculations could assign a Cu(I)/Cu(III)-cycle to the reaction and demonstrate why a higher oxidation state of copper cannot catalyze the reaction. A mechanism whereby Cu(II)-catalyst precursors can enter the Cu(I)/Cu(III)-cycle is suggested. Three low-energy pathways were found for the formation of aziridines, where the two new N-C bonds are formed either in a nonradical concerted or consecutive fashion, by involvement of singlet or triplet biradicals. A close correspondence was found between the title reaction and the Jacobsen epoxidation reaction in terms of spin-crossings and the mechanism for formation of cis/trans isomerized products. The kinetic part of the study showed that the reaction is zero order in alkene and that the rate-determining step is the formation of a metallanitrene species.

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Optically active allylic alcohols can be prepared via rearrangement of epoxides using chiral lithium amides, but other than for a small subset of meso-epoxides, insufficient reactivity and enantioselectivity hamper the existing methods. Furthermore, the chiral reagents are often required in large excess. This study presents a general and highly enantioselective process that, in addition, is based on catalytic amounts (5 mol %) of enantiopure (1S,3R,4R)-3-(1-pyrrolidinyl)methyl-2-azabicyclo[2.2.1]heptane and lithium diisopropylamide as the stoichiometric base. The influence of structural modification of the catalyst is studied in terms of activity, enantioselectivity, and aggregation behavior. The utility of the process is demonstrated by its application to a variety of epoxide derivatives (g94% ee for 11 out of 14 examples), including the formal syntheses of, e.g., a prostaglandin core unit, epibatidine, carbovir, faranal, and lasiol. The system is readily extended to the resolution of racemic epoxides, which allows access to highly enantioenriched epoxides or allylic alcohols, even at conversions near 50%.

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