CONVERSION OF ALLYLIC ALCOHOLS INTO ALLYLIC NITROMETHYL COMPOUNDS VIAA PALLADIUM-CATALYZED SOLVOLYSIS - AN ENANTIOSELECTIVE SYNTHESIS OF AN ADVANCED CARBOCYCLIC NUCLEOSIDE PRECURSOR

A two-step reaction sequence to homoallylic nitro compounds from allyl ic alcohols is presented. Ethoxy carbonylation of the alcohols with et hyl chloroformate provides the corresponding allylic ethyl carbonates in high yields. Exposure of these substrates to catalytic palladium(0) in CH3NO2 initiates a reaction sequence, ionization - decarboxylation - nitromethylation, that culminates with the formation of nitroalkene s. The regio- and stereochemical outcomes of the nitromethyl allylatio n reaction can be explained by the behavior of the transient pi-allylp alladium complexes. This methodology serves as a centerpiece for the s ynthesis of an important carbocyclic nucleoside intermediate.