Results and Discussion

1,5-Hydrogen transfer

In contrast to the ether bond cleavage, this mechanisms consists of two subsequent steps. In the first step, a hydrogen is transferred from a methyl group to the ipso carbon of the adjacent monomeric unit. The formed biradical can than dissociate in a subsequent reaction to fragments with a quinonemethide and a phenolic structure. The results are summarized in table 3 and displayed in figure 3.

Step 1 (Hydrogen Transfer):  I  ---> II(TS) ---> III
Step 2 (Ether cleavage):    III ---> IV(TS) --->  V

Table 1: Calculated state energies for the 1,5-hydrogen transfer and the subsequent ether bond cleavage. Energies given in kJ/mol.

Conformer	State	E(State)
I	S0	0.0
	T1	339.1
	S1	424.1
II (TS)	S0	191.2
	T1	337.0
	S1	485.2
III (Intermediate)	S0	134.7
	T1	165.3
	S1	357.4
IV (TS)	S0	188.1
	T1	321.3
	S1	417.3
V	S0	61.6
	T1	267.2
	S1	422.2

Fig. 3: 1,5-Hydrogen Transfer

Results Overview

Results ether cleavage