P. Muller et al., THE RHODIUM(II)-CATALYZED AZIRIDINATION OF OLEFINS WITH NITROPHENYL)SULFONYL]IMINO)PHENYL-LAMBDA(3)-IODANE, Canadian journal of chemistry, 76(6), 1998, pp. 738-750
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.