DEVELOPMENT OF THE COPPER-CATALYZED OLEFIN AZIRIDINATION REACTION

Soluble Cu(I) and Cu(II) triflate and perchlorate salts are efficient catalysts for the aziridination of olefins employing (N-(p-tolylsulfon yl)imino)phenyliodinane PhI=NTs, as the nitrene precursor. Electron-ri ch as well as electron-deficient olefins undergo aziridination with th is reagent in 55-95% yields, at temperatures ranging from -20 degrees C to +25 degrees C. The catalyzed nitrogen atom-transfer reaction to e nol silanes and silylketene acetals has also been developed to provide facile syntheses of alpha-amino ketones. Other metal complexes were f ound to be less effective at catalyzing the reaction, while PhI=NTs pr oved to be superior to other imido group donors as the nitrene precurs or. Reaction rates and yields are enhanced in polar aprotic solvents s uch as MeCN and MeN0(2). Reaction stereospecificity in the aziridinati on of cis and trans disubstituted olefins was evaluated and found to b e both catalyst and substrate dependent. Intermolecular competition ex periments between pairs of mono- and disubstituted olefins indicate th at the olefin selectivity profile for the reaction is independent of t he oxidation state of the copper catalyst employed. It is concluded th at these reactions are proceeding through the 2+ catalyst oxidation st ate under the conditions employed in this study.