The alpha-TSA method has been developed for the cleavage of beta-O-4 linkages in lignin. It consists of three steps: ( 1) thioetherification at alpha-position of beta-O-4 substructures, ( 2) sulfonylation, and ( 3) mild alkali treatment of the alpha-sulfone derivative. The method was tested on a nonphenolic dimeric beta-O-4 lignin model compound, namely on 4-benzyloxy-3-methoxyphenylglycerol-beta-guaiacyl ether. It demonstrated that the mild alkali degradation of the alpha-sulfone derivative proceeds efficiently, i.e., the electron-withdrawing sulfone group at alpha-position contributes to the cleavage of the beta-O-4 linkage in the same mechanism as that in the gamma-TTSA method.