Catalytic asymmetric heterogeneous aziridination of alkenes using zeolite CuHY with [N-(p-tolylsulfonyl)imino]phenyliodinane as nitrene donor

Copper-exchanged zeolite Y (CuHY) is found to be a highly effective heterog eneous catalyst for the aziridination of alkenes using [N-(p-tolylsulfonyl) imino]phenyliodinane (PhI=NTs) as the nitrogen source. Exchange of zeolite Y with other cations (Ag+, Co2+, Fe3+, Mg2+, Ni2+, Zn2+) was found to be in effective. This is considered to be due to the ability of these metals to c atalyse the breakdown of the PhI=NTs reagent into iodobenzene and toluene s ulfonamide. Modification of the CuHY catalyst with bis(oxazolines) leads to preparation of the first heterogeneous enantioselective aziridination cata lyst and the results showing the effect of temperature and modifier concent ration are described and discussed. A pyridine-bridged bis(oxazoline) was o bserved to give the highest enantioselectivity of 61% ee for the aziridinat ion of styrene using acetonitrile as solvent and at -10 degrees C.