Fe-Catalyzed Multicomponent Reactions: The Regioselective Alkoxy Allylation of Activated Olefins and its Application in Sequential Fe Catalysis

We present herein a versatile and broadly applicable Fe-catalyzed regioselective alkoxy allylation of activated double bonds. Substituted allylic carbonates are converted into the corresponding sigma-enyl Fe complexes by reaction with Bu4N[Fe(CO)3(NO)] (TBAFe) at 30 degrees C. The liberated alkoxide adds to an activated double bond with the generation of a C-nucleophile, which is trapped by the sigma-enyl Fe complex in a regioselective manner. Alternatively, the alkoxide acts as a base in deprotonating an external pronucleophile, which undergoes Michael addition. The method is characterized by a broad functional group tolerance, mild reaction conditions, low catalyst loadings, and high regioselectivities in favor of the ipso-substitution product.