The occurrence of non-cyclic benzyl ether bonds in lignin

Summary The structure of the non-cyclic benzyl aryl (-0-4) ethers 4 and 5, proposed by Freudenberg and Friedmann (1960) and recently boubted by Leary (1980), is discussed on the basis of previously published experimental results. Further evidence in favor of the occurrence of non-cyclic -0-4 bonds in lignin is provided. A critical comment is, however, given on the formation of non-cyclic -0- bonds in lignin according to Leary (1980).