9, 10-disubstituted phenanthrenes

Much more recently, and with the advantage of sophisticated NMR techniques that have become available since the early 1970s, it has been shown that the spiro-3i/-pyrazole structure for 29a is incorrect. It is known that the outcome of diazocyclopentadiene addition to dimethyl acetylenedicarboxylate is dependent upon the five-membered ring substituents In the case at hand, tetraphenyldiazocyclopentadiene adds to the alkyne to give 29a as a labile product that rearranges under the reaction conditions to the 3H-indazole 30a (Scheme 3) 1,3-di-r-butyldiazocyclopentadiene behaves similarly l Thus in the formation of 31a at least, the spiropyrazole 29a is not the substrate and one must question the nature of the educt (29 versus 30) employed in cycloproparene synthesis by the spiro-3i/-pyrazole route. Nonetheless, there can be little doubt that spirocycle 29d is the substrate employed by Mataka and coworkers because, upon thermolysis, the corresponding indazole 30d was isolated. What must be noted here is that the thermal reaction did not provide any of the cyclopropa[/]phenanthrene 31d, but neither did independent photolysis of the isolable indazole 30d in benzene solution a 9,10-disubstituted phenanthrene is formed from diradical interaction with the solvent (equation 7). 

The reaction of 2-iodobiphenyl (162) with alkynes offers a good synthetic method of 9,10-disubstituted phenanthrenes 164. The intermediate 163 undergoes attack on an aromatic ring as one possibility [54]. The reaction of functionalized diarylacetylene 165 with 162 was applied to the syntheses of an analog of antiviral agent hypericin 167 via 166 [55]. Also the indolocarbazole 169 was prepared from 3-iodobiindole 168 by attack on the indole ring [56]. 

Gomplexes 36 and 37 (R = Bu ) are active catalysts for the insertion of R-G=G-Ph into biphenylene to form 9,10-disubstituted phenanthrenes (Scheme 4). Significantly, no cyclotrimerization of the alkyne was observed as long as biphenylene was present, but in its absence hexaphenylbenzene was produced from PhG=GPh at a slow rate (ca. 0.4 turnover/day). On the other hand, the GF3 derivative did not promote the formation of phenanthrenes, leading instead to the formation of cyclic trimers (Scheme 5). The proposed mechanism for the insertion of alkynes into biphenylene involves the dissociation of the Ni-NMe2 moiety to allow the coordination of the incoming biphenylene... 

The reactions of arynes with allenes followed by olefln isomerization produces 9,10-disubstituted phenanthrenes. In 2007, Li et al. reported that electron-deficient allenes 47 react with arynes from 46 in the presence of [(allyl)PdCl]2/P(o-tol)3 catalyst and CsF to produce phenanthrenes 48 (Scheme 6.15) [17]. 

Aryl pinacol has been known to undergo the pinacol rearrangement to yield a pinacolone-like product. When arylpinacol reacted with TfOH, 9,10-disubstituted phenanthrene was produced in high yield (Scheme 2.15) [40]. 

In a later study, persistent carbocations were generated from five A-ring mono-and disubstituted phenanthrenes [3-OMe, 4-OMe, 1,3-bis(OMe), 2,4-bis(OMe), and... 

Section III, A, 1. Theilacker and Baxmann (1953a) have discussed the difficulties of preparing 4,5-disubstituted phenanthrenes owing to the overcrowding at these positions. They have successfully resolved l,8-diamino-4,5-dimethylphenazine (68) (Theilacker and Baxmann,... 

As in 4,5-disubstituted phenanthrenes, substitutions at the sterically most hindered Cl and CIO positions of 4,7-phenanthroline as depicted in 49 (Fig. 15) cause helical twist of the aromatic structure [54]. The first example of such derivatives, 1,10-dicarboxy-3,8-diphenyl-4,7-phenanthroline (50), was reported in 1932 (Scheme 9) [55]. Condensation of p-phenylenediamine with benzaldehyde and then with pyruvic acid followed by cyclization produced 50. Oxidation of 50 to tetracarbox-ydipyridyl 51 provided the supporting evidence for the formation of 50. 

The thermal intramolecular 2 + 2-cycloaddition of 4,4,-disubstituted-2,2/-bis(phenyl-ethynyl)biphenyls (1) yielded the intermediate l,2-diphenylcyclobuta[l]phenanthrenes (2), which could be trapped with 2,3,4,5-tetraphenylcyclopenta-2,4-dione (3) to produce the Diels-Alder adduct (4). Thermal decarbonylative ring opening of (4) gave 9,10,11,12,13,14-hexaphenylcycloocta[l]phenanthrenes (5) as the final product in 12-23% yield (Scheme l).1... 

There are no reported alternatives to the current procedure for the acylation of a phenanthrene using the Friedel-Crafts reaction. Indeed, alternative methods to cleanly prepare 3,6-disubstituted derivatives of phenanthrene by means of electrophilic substitution are not known,5> >" nor is there a... 

When the indazene route was applied to cyclopropa[/]phenanthrene, the reaction product was not the expected cycloproparene, but a 9,10-disubstituted phcnanthrene, which is derived from reaction of the intermediate diradical with the solvent. ... 

The samples from South Carolina (Sample 18) and Yosemite National Park (Sample 29) demonstrate a peculiar abundance pattern in the phenanthrene/anthracene series. The nonsubstituted and disubstituted species are both abundant relative to the monosubstituted phenanthrenes/ anthracenes. Information from the mass spectral analysis of other components in these soil extracts indicates the source for these particular PAH is neither combustion nor fossil fuels but rather aromatization of certain natural products (2). 

Several 5,8-disubstituted l,12-dimethylbenzo[c]phenanthrenes, including diacid 70 [63, 64], diacetylene 71 [65], diamine 72 [66], and the tetranitro derivative 73 [66], have also been synthesized and resolved. The charge transfer complex between (M)-73 and electron-rich (M)-72 was found to be more stable than the complex between (M)-73 and (P)-12. 

Following the same methodology, the photostimulated reaction of the anion of 9-phenanthryl amide with ArX gave 10-aryl phenanthren-9-amines (75-100%) [51].The double arylation of 9-phenanthryl amide with p-bromoiodobenzene afforded 40% yield of the disubstitution... 

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