Arylation diphenylmethane

Although treated as separate classes in the Colour Index, these structural types are closely related and the few diphenylmethane dyes such as auramine (1.28 Cl Basic Yellow 2) are now of little practical interest. Commercial usage of the triarylmethane dyes and pigments has also declined considerably in favour of the major chemical classes. They were formerly noteworthy contributors to the acid, basic, mordant and solvent ranges, primarily in the violet, blue and green sectors. Numerous structural examples are recorded in the Colour Index. The terminal groupings can be amine/quinonimine, as in auramine and crystal violet (1.29 Cl Basic Violet 3), hydroxy/quinone, or both. The aryl nuclei are not always benzenoid (section 6.5). 

Diphenylmethane and triphenylmethane dyes are monomethine dyes with two or three terminal aryl groups, of which at least one, but preferably two or three, are substituted by a donor group para to the methine carbon atom. The most important donor is the amino group. Important dyes belonging to this class include the well-known malachite green (12) [9] and crystal violet (13) [10], which are some of the oldest synthetic cationic dyes ... 

Single-crystal X-ray structures have been reported for the following aryl- and heteroaryliodo-nium salts diphenyliodonium triiodide [412], (2-methylphenyl)(2-methoxyphenyl)iodonium chloride [413], (2-methoxy-5-methylphenyl)(4-methoxy-2-methylphenyl)iodonium trifluoroacetate [414], (2-methoxy-5-methylphenyl)(4-methoxyphenyl)iodonium trifluoroacetate [415], a complex of diphenyliodonium tetrafluoroborate with pyridine [416], a complex of diphenyliodonium tetrafluoroborate with 1,10-phenanthroline [417], a complex of diphenyliodonium tetrafluoroborate with 18-crown-6 [418], 1-naphthylphenyliodonium tetrafluoroborate [419], 3,10-dimethyl-10//-dibenzo[, e]iodinium tetrafluoroborate [420], aryl(pentafluorophenyl)iodonium tetrafluoroborates [421], 4,4 -[bis(phenyliodonium)]-diphenylmethane ditriflate [422], [bis(4-methoxyphenyl)](diethylaminocarbodithioato)iodine(in) [423], di(p-tolyl)iodonium bromide [424], diphenyliodonium chloride, bromide and iodide [425,426], diphenyliodonium nitrate [427], diphenyliodonium tetrafluoroborate [428], thienyl(phenyl)iodonium salts [401], (anft-dimethanoanthracenyl)phenyliodonium tosylate and hexafluorophosphate [429] and 3-mesityl-5-phenylisoxazol-4-yl(phenyl)iodonium p-toluenesulfonate [409]. 

Specifically, diphenylmethane was prepared in >90% yield by the reaction of either Ph4Sn or PhjSnMe with BrCH2Ph in the presence of PhCH2Pd(PPh3)2Cl.t The synthesis of polychlorinated diaryhnethanes shown in Scheme 26 is noteworthy despite the modest product yields. Most of the other currently known examples of Pd-catalyzed aryl-benzyl coupling pertain to the synthesis of heteroarenes (Scheme 27). 

The acid-catalysed rearrangement of benzyl phenolic ethers to diphenylmethane compounds and the rates of rearrangement of (Z)-aryUiydrazones of 5-amino-3-benzoyl-l,2,4-oxadiazole into (2-aryl-5-phenyl-2H-l,2,3-triazol-4-yl)ureas have been reported. ... 

Under similar conditions as above, Sun et al. studied several a,co-diaryl-alkanes. For two identical aryls attached to an alkane, e.g., diphenylmethane, dinaphthylmethane, etc., the superdelocalizability concept predicted the transfer of the first H radical from the AC surface to Car of the Car-Calk bond. For diphenylmethane, after HCR, the resulting product would be mainly benzene and toluene. Similar reactions would be expected for dinaphthylmethane. However, in the case of different aryls, e.g., phenylnaphthylmethane, hydrogen radical added preferentially to the Car of the Car-Calk bond on the side of the larger aryl giving (after HCR) toluene and naphthalene with only... 

Shi and co-workers disclosed the use of DDQ for the direct arylation of diphenylmethane derivatives. A variety of electron-rich aromatic substrates were successfully coupled with the benzylic C-H bonds of diphenylmethane catalyzed by FeCl2, and gave the corresponding products in good-to-excellent yields. The methojy group of aromatic substrates played an important role in regioselectivity. Orthoester-, acetojq -, carboxy-, carbonyl-, and... 

Reductions. In contrast to hydrosilylation reactions catalyzed by metal chlorides, aldehydes and ketones are rapidly reduced at rt by Triethylsilane and BF3 -OEt2, primarily to symmetrical ethers and borate esters, respectively. Aryl ketones like acetophenone and benzophenone are converted to ethylbenzene and diphenyl-methane, respectively. Friedel-Crafts acylation-silane reduction reactions can also occur in one step using these reagents thus Benzoyl Chloride reacts with benzene, triethylsilane, and BF3-OEt2 to give diphenylmethane in 30% yield. ... 

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