Photochemical reactions of trans-anethole
1968; Elsevier BV; Volume: 24; Issue: 5 Linguagem: Inglês
10.1016/0040-4020(68)88120-7
ISSN1464-5416
AutoresH. NOZAKI, Ikue Otani, Ryōji Noyori, Mituyosi Kawanisi,
Tópico(s)Oxidative Organic Chemistry Reactions
ResumoA novel dimer of trans-anethole has been obtained photochemically. The dimerization proceeds with strict stereospecificity and the structure of the dimer has been ascertained as 1,cis-2-di-p-anisyl-trans-3,trans-4-dimethylcyclobutane. The dimer was transformed into the corresponding diphenol, diacetate and 1,cis-2-dimethyl-trans-3,trans-4-diphenylcyclobutane. The hydrocarbon was independently obtained from β-truxinic acid by reduction. Some dimethyldiphenylcyclobutane isomers have been prepared analogously from cinnamic acid dimers and the NMR spectra have been compared. Anethole reacts photochemically with benzaldehyde and benzophenone to afford the corresponding oxetanes, some of which decompose spontaneously into stilbenes and acetaldehyde. The anethole dimer was not obtained in the presence of such carbonyl compounds, while isomerization to cis-anethole proceeds smoothly. Salicylaldehyde gives another type of 1:1-adduct, which has been shown to be 4-p-anisyl-2-hydroxy-3-methylchroman. An analogous hemiacetal was obtained by the reaction of salicylaldehyde and 1,1-diphenylethylene. Mechanistic implications of anethole photochemistry have been discussed.
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