REGIOSELECTIVE ACYLATIVE CLEAVAGE OF CYCLIC ETHERS CATALYZED BY RARE-EARTH COMPOUNDS

Five-membered ring ethers can be cleaved and acylated in the presence of acyl chloride and 1% Cp2YCl or 10% LnCl3 under mild conditions. Hea vy rare earth trichlorides are much more catalytically active than the light ones. 2-Substituted tetrahydrofurans are regioselectively cleav ed at the secondary C-O bond to give the corresponding secondary chlor ides. The preparative usefulness of this cleavage reaction over the ex isting ones, resides in its higher selectivity and convenience.