Ruthenium-Catalyzed Allylation of Aromatic Compounds and Allylic Ether Formation

Ruthenium-catalyzed allylation of aromatic compounds such as benzene, toluene, p-xylene,
anisole, phenol, furans, and thiophenes with allylic alcohol derivatives gives the corresponding allylated products in good to high yields with a high regioselectivity. Only the cationic
thiolate-bridged diruthenium(III, III) complexes promote the reaction. Investigation of the
allylation pathway in the reaction of cinnamyl alcohol with p-xylene has revealed that it
proceeds via two ways:  a direct allylation with the alcohol itself and an allylation with
dicinnamyl ether formed as an intermediate. A new cationic thiolate-bridged diruthenium(III, IV) complex together with allylated cinnamyl chlorides has been formed in the reaction
of the diruthenium(III, III) complex with cinnamyl chloride, this new complex being revealed
to be effective as an allylation catalyst. The cationic diruthenium(III, III) complexes can
also catalyze the allylation of simple alcohols with allylic alcohols to give the corresponding
alkyl allylic ethers in high yields with complete regioselectivity. These reactions provide
useful methods for allylation of some aromatic compounds and allylic ether formation.