GENERATION OF NITRILE OXIDES THROUGH O-METALATION OF HYDROXIMOYL CHLORIDES - CHELATION-CONTROLLED SYN-SELECTIVE CYCLOADDITION OF NITRILE OXIDES TO ALPHA-SUBSTITUTED ALLYL ALCOHOLS
New generation of nitrile oxides by treatment of hydroximoyl chlorides with organometallics is reported. Thier cycloadditions to the allyl alcohols bearing a chiral center at the 1-position proceed in a syn-selective manner, providing the first example of stereocontrol of 1,3-dipolar cycloaddition by the aid of metal chelation.