Abstract:
2-Acetyl containing a neighbouring aromatic ether group regioselectively
reacts with the cyclopentene in the presence of cationic Ru-H catalyst
[(C6H6)(PCy3)(CO)RuH]+BF4−
in aromatic hydrocarbon solvents. The alkyl
moiety of ether can be any of cyclic, methyl, butyl, benzyl, phenyl and allyl
groups. Chelation plays a key role in regioselectivity directing the C-O bond
cleavage reaction. The reactions of 2-acetyl derivatives of aryl-ethers under
these conditions affect the corresponding products having onlyphenol -OH
group at the aromatic ring. Cleavage of the sp3 C-O bond occurs selectively
rather than sp2 C-O bond. The method has successfully extended to C-O
bond cleavage of flavanone biomolecule and strongly possible to extend
regioselectively depolymerize lignin biomolecules.
