Synthesis and crystal structure determination of model compounds for the dibenzodioxocine structure occurring in wood lignins
Model compounds for the dibenzodioxocine structure, a new structural unit recently discovered in wood lignins, have been synthesised by two different methods. In one route, the 8-membered ring is formed by ring closure of an arylglycerol β-aryl ether with a 5,5′-biphenyl structure in the aryl ether moiety. The other, which gave better yields, involves a biomimetic oxidative phenol coupling. Crystal structures have been obtained for one β-aryl ether and of two dibenzodioxocine isomers, as well as of a product of acid hydrolysis containing a 7-membered ring structure.