THE RHODIUM(II)-CATALYZED AZIRIDINATION OF OLEFINS WITH NITROPHENYL)SULFONYL]IMINO)PHENYL-LAMBDA(3)-IODANE

The aziridination of olefins with nitrophenylsulfonyl)imino)phenyl-lam bda(3)-iodane, NsN=IPh (1c), in the presence of [Rh-2(OAc)(4)] proceed s in yields of up to 85% when the olefin is used in large excess. Unde r optimized conditions, styrene (4a) is aziridinated with 1 equiv. of NsN=IPh (1c) in 64% yield with 2 mol% of catalyst. The aziridines deri ved from electron-rich olefins undergo ring-opening under the conditio ns of the aziridination and afford rearrangement products or pyrrolidi nes. The aziridination is sterospecific with 1,2-dialkyl- and 1,2-aryl alkyl-disubstituted olefins, but nonstereospecific with stilbene. The rho-value for aziridination of substituted styrenes is -0.61. No ring- opened products are observed upon aziridination of vinylcyclopropanes. Tn the presence of chiral Rh-II catalysts, the aziridination is enant ioselective, affording an ee of 73% with cis-beta-methylstyrene (4k) a nd 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.