Azulenophane

The photoinduced desulfurization of macrocyclic sulfides in the presence of triethyl phosphite has been widely used in the synthesis of cyclophanes. The [2.2](l,3)-azulenophane (302), for example, has been prepared in this way from the 2,13-dithia[3.3]azulenophane (303).245 Numerous other... 

Grinune S, Mennicke W, Vogtle F, Nieger M (1999) Experimental and theoretical studies of a chiral azulenophane synthesis, structure and circular dichroism spectra of 14,17-dimethyl[2]... 

Fujimura, M., Nakazawa, T and Murata, I., A novel coupling reaction of 1-azulylmethyl-trimcthylammonium iodide synthesis of l,2-bi.s(I-azulyl)ethane and 12.2.2.21(1.3)-azulenophane. Tetrahedron Lett., 825, 1979. 

Polycyclic aromatic hydrocarbons can be bent by bridging in a similar fashion. Two recent examples of such [n] cydophanes are azulenophane 116 [77] and 1,8-dioxa[8](2,7)pyrenophane 117 [78]. X-ray structure analysis revealed an angle of 3.7° between the azulene ring planes, whereas the pyrene moiety is bent by nearly 90°. 

Among other macrocyclic azulene derivatives, sulfur-containing metacyclo(l,3)azulenophanes (e.g., 162) have been described (79MI2). 

Improved syntheses of bitropyl and sym-tetrabenzobitropyl have been reported whereby tropylium tetrafluoroborate and dibenzotropylium tetrafluoroborate, respectively, are coupled using vanadium(ii) chloride or titanium(iii) chloride. Trimethylene-8,8-dithiaheptafulvene (125), an electron-rich heptafulvene, has been prepared from the adduct of 2-lithio-l,3-dithian and tropylium tetrafluoroborate, and its reactions with reactive dienophiles have been examined. " The sym-dibenzo analogue of (125) has also been described.anti-[2,2] (2,6)-Azulenophane has been prepared by the dimerization of (126). ... 

The azulenophanes, e.g. (25), and (26) have been made. Their syntheses required elaboration and ring-expansion of pre-formed [2,2]cyclophanes on the one hand and, on the other, the coupling of an azulene derivative with the appropriate dithiol followed by photolytic desulphurisation. 

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