Dibenzo cyclooctene

Dibenzo[ /]cycloocten-5-one 302 was transformed by Baeyer-Villiger oxidation into the substituted 6-oxodibenzo-[b,f oxonin 303 (Equation 42) <1996T8063>. The regiochemistry of the process and structure of the product was assigned based on H NMR data and their comparison to theoretical chemical shifts of the product and of the hypothetic dihydrodibenzo[ , g]oxonin-5(7//)-one isomer. 

Dibenzo[a,d]cyclooctene, 5,6,7,12-tetrahydro-Dibenzo[a,d]cyclooctene, 5,6,7,12-tetrahydro-conformation, 7, 706... 

Figure 8.6 EPR spectrum of the dibenzo[a,e]cyclooctene radical cation showing hyperfine structure. The radical was generated by UV irradiation of the neutral parent molecule. From Gerson, F., Felder, P., Schmidlin, R. and Wong, H. N. C., J. Ghent. Soc., Ghent. Gommun., 1659-1660 (1994). Reproduced by permission of The Royal Society of Chemistry.

An improved method for the preparation of selenacrown ethers has been described by Xu and co-workers. The synthesis of poly-(o-diselenobenzene) was detailed as the key intermediate for the syntheses of o-benzene diselenium type of selenacrown ethers. Under alkaline conditions, 5,6,1 l,12-tetraselena-dibenzo[tf/]cyclooctene 212 was reduced with potassium borohydride to give o-benzenediselenolate anion 213, which condensed with dihalides 215-217 and different 12- and 24-membered selenacrown ethers 218 and 219 were isolated in good yields (Scheme 31) C1995MI1559, 1997JCD1043, 1999JCD1039>. 

Ph2C=NEt " ), dibenzo[fl,e]cyclooctene (54, a nonplanar cation radical)," ... 

Liu, K.T., Lesca, P. Pharmacological properties of Dibenzo (a,c) cyclooctene derivatives isolated from fructiis Schizandra chinensis III. Inhibitory effects on carbon tetrachloride-induced lipid peroxidation, metabolism and covalent binding of carbon tetrachloride to Hpids. Chem. Biol. Interact. 1982 41 39-47... 

Table 24.25 Synthesis of aryl adduct, diendiynes, and dibenzo[a,e]cyclooctenes [10] ...

R Aryl adducts Yield (%) Diendiynes Yield (%) Dibenzo[a,e] cyclooctenes Yield (%)... 

The treatment of silyl derivatives of diendiynes with TBAF triggers a cascade sequence, initiating from the desilylated diendiynes, and through benzocy-clobutadienes afford dibenzo[a,e]cyclooctenes (syn-dibenzocyclooctatetraenes) (Scheme 24.31 Table 24.25) [10]. 

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