Reactions of fluorene

For example, Fig. 10.37 shows a mutagram of an extract of ambient gas-phase POM collected on polyurethane foam plugs in Claremont, California, along with mutagrams of the extracts of PUF samples collected from environmental chamber studies of the OH radical initiated reactions of fluorene and naphthalene, respectively (Arey et al., 1992 Harger et al., 1992 Atkinson and Arey, 1994). Clearly, the mutagrams from the OH-initiated reactions are very similar to that of ambient air. 

Helmig, D., J. Arey, R. Atkinson, W. P. Harger, and P. A. McElroy, Products of the OH Radical-Initiated Gas-Phase Reaction of Fluorene in the Presence of NOx, Atmos. Environ., 26A, 1735-1745 (1992c). 

The increase in the electron acceptor concentration in a solution transforms the reaction of fluorene oxidation into regime when the first stage (deprotonation of fluorene) limits the chain process. For the oxidation of other alkylaromatic hydrocarbons, see Refs. [292 304]. 

Data for the substitution reactions of fluorene, Table 8, are more restricted. In the chlorination of fluorene (Beaven et al., 1962) merely 69% of the chlorine is consumed with the formation of 4-chlorofluorene. Appreciable quantities of the halogen are diverted to addition products as with biphenyl and phenanthrene. 

SUMMARY OF NICI REACTIONS OF FLUORENE CHARACTERIZED BY FTMS... 

Acetylfluorene has been prepared by the reaction of fluorene with acetic anhydride or with acetyl chloride in the presence of aluminum chloride in carbon disulfide or in nitrobenzene. When nitrobenzene is employed as the solvent it must be removed by a time-consuming steam distillation, and the use of acetyl chloride as a reagent leads to the formation of considerable amounts of 2,7-diacetylfluorene. 

The reaction of fluorene with alkali metals (example 5) proceeds by way of radical anions or dianionswhose rate of decay increases Li" < Na < < Cs. ... 

Direct reaction of fluorene with alkali metals is not recommended. It proceeds via radical-anions and yields some side products. 

The preparations and utility of these solvent complexes are illustrated by the syntheses of [M(fj -CsMe5)(NCMe)3] (M = Rh or Ir) and the synthesis of the fluorene complex [Ir(> -C5Me5)( / -Ci3Hio)][PF6]2 from the in situ reaction of fluorene with the acetone complex [Ii (>j -CsMejXMe2CO)3]-... 

Recently, a new synthetic protocol for synthesis of 9-arylfluorenes or 9,9-diarylfluorenes was reported wherein these products were furnished in good to excellent yields by Pd-catalyzed cross-coupling reactions of fluorene with haloarenes [141]. This synthetic method was also applied in the preparation of aryl-substituted sumanenes. Palladium-catalyzed arylation of sumanene (2) was conducted with l-bromo-2,6-dimethylbenzene, and the desired xylylsumanene 124-xyl was... 

The corresponding 1,5,2-oxathiazole 5-oxide is also obtained in the reaction of fluorene-sulfine and benzonitrile oxide... 

Cremlyn et aV examined the reaction of fluorene 39 with excess chlorosulfonic acid (six or twelve equivalents) or less reagent (three equivalents) in thionyl chloride. In each case, the product appeared to be a 1 1 mixture of the 2-sulfonyl chloride and the 2,7-disulfonyl chloride. The latter compoimd was obtained as the major product when fluorene-9-carboxylic acid was treated with a large excess of chlorosulfonic acid (twelve equivalents) in boiling chloroform (2 hours). ... 

Short DBF oligomers have been synthesized by small-molecule-oriented synthetic method (Fig. 5) [39,40]. In this case, reaction of fluorene with paraformaldehyde in the presence of a base afforded a dimer having hydrogen atoms at the terminals. 

One of the first examples was the above mentioned work from Yoshino et al. [7] concerning the synthesis of poly(9,9-dialkylfluorene)s via oxidative coupling of fluorene derivatives. Poly(9,9-dialkylfluorene) derivatives have been also synthesized via Ni- and Pd-catalyzed aryl-aryl homo- and cross-coupling reactions of sui-... 

In 75 % aqueous acetic acid, the bromination of fluorene at 25 °C obeys second-order kinetics in the presence of bromide ion and higher orders in its absence287, with Ea (17.85-44.85 °C) = 17.4, log A = 10.5 and AS = —12.4 however, these values were not corrected for the bromine-tribromide ion equilibrium, the constant for which is not known in this medium, and so they are not directly comparable with the proceeding values. In the absence of bromide ion the order with respect to bromine was 2.7-2.0, being lowest when [Br2]initial was least. Second- and third-order rate coefficients were determined for reaction in 90 and 75 wt. % aqueous acetic acid as 0.0026 and 1.61 (k3/k2 = 619), 0.115 and 12.2 (k3/k2 = 106) respectively, confirming the earlier observation that the second-order reaction becomes more important as the water content is increased. A value of 7.25 x 106 was determined for f3 6 (i.e. the 2 position of fluorene). 

Sc Hr.MR 4, Mechanism for the production of 9-(silylmelhyl)fluorenes from the reaction of biphenyl with (dichloroethyl)silane. 

A full account has appeared of the reactions of the 2 1 fluorene-triethyl phosphite adducts on heating and with acetonitrile. 

A series of new palladium complexes 26 bearing a phosphine-functionalised NHC ligand has been shown to be more efficient than typical catalytic systems (i.e. Pd(OAc), PPhj) for the reaction depicted in Scheme 7.10 [55], In fact, these conditions afforded the 9-benzylidene-97f-fluorene in higher yields when iodobenzene was used, whereas the reaction of the less reactive phenyl bromide with diphenylacetylene was achieved for the first time affording the desired product in moderate to good yields. 

A simple synthesis of fluorenes as 4-297 was developed by Schafer and coworkers, also using a combination of a Claisen rearrangement and a carbonyl ene reaction (Scheme 4.63) [100]. Heating 4-295 in xylene at 180 °C led to 4-297 as a single diastereomer in 73 % yield the phenol 4-296 can be assumed as an intermediate, but this could not be detected in the reaction mixture. 

In the absence of capping ligands, polymeric alkynylmercury derivatives can be readily prepared. Polymer 57 is formed by reaction of HgC with 9,9-bis(4-ethynylphenyl)-fluorene in a basic methanolic solution. This polymer, whose average molecular weight (/I7W) is only 8,900, shows a strong triplet emission of the organic chromophore enhanced by the presence of the mercury heavy atom.69... 

The results of a thorough study of the kinetics, products and stereochemical course for the nucleophilic substitution and elimination reactions of ring-substituted 9-(l-Y-ethyl)fluorenes ([31]-Y, Y = Br, I, brosylate) have been reported (Scheme 19).121,122. The reactions of the halides [31]-Br and [31]-I were proposed to proceed exclusively by a solvent-promoted ElcB reaction or an E2 reaction with a large component of hydron transfer in the transition state .122... 

Just as disulfonium dication 34, diselenonium 113 and ditelluronium dication 114 do not undergo deprotonation. Instead, reaction of dication 113 with fluorenyllithium affords bis-selenide and fluorene dimer 103.96 Softer Lewis base such as ra-tolyl magnesium bromide reacts with diselenonium-dication 113 to give 127, a product of nucleophilic substitution at the onium atom (Scheme 48).129... 

Kwok, E.S.C., Atkinson, R., Arey, J. (1997) Kinetic of the gas-phase reactions of indan, indene, fluorene, and 9,10-dihydroanthracene with OH radicals, NOs radicals, and 03. Int. J. Chem. Kinet. 29, 299-309. 

HTAB has been used, on the one hand, to increase the CL intensity of the reaction of 2,6,7-trihydroxy-9-(4 chlorophenyl)-3-fluorene with hydrogen peroxide in alkaline solution, in the presence of traces of Co(II) as a catalyst [43]. As a consequence, a CL method has been established for determination of ultratraces of Co(II). On the other hand, HTAB micelles sensitize the CL oxidation of pyro-gallol with A-bromosuccimide in an alkaline medium [44], while anionic and nonionic surfactants inhibit the CL intensity of this reaction (Table 3). This sensitized process allows the determination of pyrogallol by flow injection in an interval of 5 X 10 7-3 X 10 5 M. 

On the contrary, the oxidation of fluorene in a basic solution is not limited by the deprotonation of hydrocarbon [284]. This is in agreement with the oxidation of fluorene and 9,9-dideuterofluorene at the same rate in DMSO and 1,1-dimethylethanol solution. The stoichiometry of fluorene oxidation is close to unity (except oxidation in HMPA) and the main product of the reaction is fluorenone. The stoichiometry and the initial rate of the reaction depends on the solvent (conditions 300 K, [fluorene] = 0.1 mol L 1, [Me3COK] = 0.2mol L 1,p02 = 97kPa). 

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