Fig. 5. Beech lignin DDQ oxidation study: (A) proposed reactivity of β–β units within lignin. Highlighted H atoms (and their corresponding cross-peaks within 2D HSQC analysis) were used for semi-quantification of units within lignin. ^a(B) Graph displaying β–β, β–β derived alcohol and β–β derived aldehyde units per 100 C9 units against DDQ weight equivalents; data repeated in triplicate, for standard error analysis, see Table S3.† All standard errors associated with values in this figure are <1%. *Dashed lines indicate a plateau where no more oxidation is notably occurring. (C) Reactivity of LBHK model 1 when treated with DDQ (see Scheme S3 and Fig. S17† for crude ¹H NMR data from reactions). ^§Proposed structure based on current analytical data (Fig. S17†).