Acylation of 1,1′-bi-2-naphthol (BINOL) ethers using Lewis acids aluminum(III) chloride and titanium(IV) chloride gave the corresponding 6,6′-diacyl derivatives in good yields.
chiral 1,1′-bi-2-naphthol - acylation - aluminum(III) chloride - titanium(IV) chloride - acyl-bi-2-naphthyl ether