Enantioselective Synthesis of Isoxazoline N-Oxides via Pd-Catalyzed Asymmetric Allylic Cycloaddition of Nitro-Containing Allylic Carbonates

A useful method for the enantioselective preparation of isoxazoline N-oxides via Pd-catalyzed asymmetric allylic cycloaddition of nitro-containing allylic carbonates has been developed. By using palladium complex in situ generated from Pd-2(dba)(3)center dot CHCl3 and phosphoramidite L2 as a catalyst under mild conditions, the transformation afforded vinylated isoxazoline N-oxides in high yields with acceptably high enantioselectivities.