Propenylphenols oxidative dimerization

Nakatsubo F, Higuchi T (1975) Synthesis of 1,2-diarylpropane 1,3 diols and determination of their configurations Holzforschung 29 193-198 Ralph J, Ede RM, Robinson NP, Main L (1987) Reactions of /f-aryl lignin model quinone methides with anthrahydroquinone and antranol J Wood Chem Technol 7 133 160 Ralph J, Young RA (1983) Stereochemical aspects of lignin model (S aryl ether quinone methide reactions J Wood Chem Technol 3 161-182 Sarkanen KV, Wallis AFA (1973) Oxidative dimerizations of (E)- and (Z) isoeugenol (2 methoxy-4-propenylphenol) and (E) and (Z)-2,6-dimethoxy-4-propenylphenol JCS Perkin I 1973 1869-1878... 

The racemate of conocarpin (7.2a), the simplest known member of this small group of neolignans, was again synthesized by oxidative dimerization (with FeCla) of/7-propenylphenol (76). 

Methylenedioxy-6-propenylphenol (42) underwent le oxidation followed by radical coupling resulting in the formation of dimeric o-quinone methide 43, which was further converted to carpanone (44) and seven-membered ether 45 in 11 and 44% yields, respectively, as shown in Scheme 8. The former is produced by an intramolecular [4 + 2] cycloaddition . Carpanone has also been synthesized using oxidants such as palladium chloride and molecular oxygen in the presence of Co(II)salen. ... 

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