1.1- Diphenylethylene, hydrogenation

A mixture of 20 g of 1. [p.((3.diethylaminoethoxy)phenyl]-1,2-diphenylethanol in 200 cc of ethanol containing an excess of hydrogen chloride was refluxed 3 hours. The solvent and excess hydrogen chloride were removed under vacuum, and the residue was dissolved in a mixture of ethyl acetate and methylene chloride. 1-[p-((3.diethylaminoethoxv)phenyl] -1,2-diphenylethylene hydrochloride was obtained, melting at 148° to 157°C. This hydrochloride salt was treated with N-chlorosuccinimide in dry chloroform under reflux. The product then obtained was converted to the free base and treated with citric acid. The dihydrogen citrate salt of 1-[p-((3-diethylaminoethoxy)phenyl]-1,2-diphenylchloroethylene was obtained, melting at 116.5° to 118°C. 

Two pieces of direct evidence support the manifestly plausible view that these polymerizations are propagated through the action of car-bonium ion centers. Eley and Richards have shown that triphenyl-methyl chloride is a catalyst for the polymerization of vinyl ethers in m-cresol, in which the catalyst ionizes to yield the triphenylcarbonium ion (C6H5)3C+. Secondly, A. G. Evans and Hamann showed that l,l -diphenylethylene develops an absorption band at 4340 A in the presence of boron trifluoride (and adventitious moisture) or of stannic chloride and hydrogen chloride. This band is characteristic of both the triphenylcarbonium ion and the diphenylmethylcarbonium ion. While similar observations on polymerizable monomers are precluded by intervention of polymerization before a sufficient concentration may be reached, similar ions should certainly be expected to form under the same conditions in styrene, and in certain other monomers also. In analogy with free radical polymerizations, the essential chain-propagating step may therefore be assumed to consist in the addition of monomer to a carbonium ion... 

Korneev and Kaufmann successfully lithiated 2-bromo-l,l-diphenylethylene (46) by bromide-lithium exchange to form 2-lithio-l,l-diphenylethylene (47). A second lithia-tion could be effected in four hours at room temperature by deprotonation of the aromatic ring with w-butyllithium in the presence of TMEDA (Scheme 17). Like in the synthesis of compound 23, the first lithiation activates the ortho-hydrogen atom of the Z-phenyl substituent to give 1,4-dilithium compound 48. In total, three equivalents of the alkyl-lithium base are required the third equivalent is consumed in the trapping reaction of w-bromobutane with generation of octane. 

The transfer hydrogenation of a-keto- S -unsaturated esters, catalyzed by Ru(p-cymene)(TsDPEN) (TsDPEN monotosylated l,2-diphenylethylene-l,2-dia-mine) with 2-propanol as the hydrogen source, has been developed as an efficient method for the preparation of a-hydroxy-)S, y-unsaturated esters or acids. 

Styrene and its derivatives, such as a-methylstyrene, atropic acid, cinnamic acid, and cinnamyl alcohol, were readily reduced (acids were added as their salts), yielding the corresponding dihydro derivatives (Table I). However, propenyl-benzene, tmst/m-diphenylethylene, and stilbene absorbed no hydrogen. 

If 1,1-diphenylethylene is treated with elemental fluorine under the same reaction conditions, C14H12F2 (compound A) is obtained in a 14% yield (accompanied by 78% of compound B). If the same compound is treated with hydrogen fluoride and lead tetrafluoride or with phenyl iodide difluoride, C14H12F2 (compound C) is produced in 27% and 47% yields, respectively. Compounds A and C are different from each other, and different from both meso- and ( )-l,2-difluoro-l,2-diphenylethane. What are the compounds A, B, and C, and how are they formed ... 

The preparation of other stereospecific hydrogenation catalysts such as ruthenium dichloride((S)-(6,6 -dimethoxybiphenyl-2,2 -diyl)bis[bis(3,5-dimethyl-xylene)((R,R)-2-diphenylethylene-diamine)] is provided (2). Other suitable ligands such as l,2-bis(2,5-dimethylphospholano)benzene are described (3). 

Recent work on the dimerisation of 1,1-diphenylethylene by aluminium chloride produced conclusive evidence that direct initiation does not lead to the total ctmsump-tion of the catalyst. This excellent piece of research diowed that about 2.5 aluminium atoms are needed to give rise to one carbenium ion. Similar indications were reported by Kennedy and Squires for the low temperature polymerisation of isobutene by aluminium chloride. They underlined the peculiar feature of limited yields obtained in flash polymerisations with small amounts of catalyst. The low conversions could be increased by further or continuous additions of the Lewis acid. Equal catalyst increments produced equal yield increments It was also shown that introductions of small amounts of moisture or hydrogen chloride in the quiescent system did not reactivate the polymerisation. This work was carried out in pentane and different purification procedures for this solvent resulted in the same proportionality between polymer yield and catalyst concentration. Experiments were also performed in which other monomers (styrene, a-methylstyrene, cyclopentadiene) were added to the quiescent isobutene mixture. The polymerisation of these olefins was initiated but limited yields were again obtained. Althou the full implications of these observations must await more precise data, we agree with the authors interpretation that allylic cations formed in the isobutene polymerisation, while incapable of activating that monomer, are initiators for the polymerisation of the more basic monomers added to the quiescent mixture. The low temperature polymerisation of isobutene by aluminium chloride was also studied... 

Arnold and his co-workers have reported the electron-transfer-induced photodimerization of 1,1-diphenylethylene. This reaction is thought to proceed to the triene (202a) which, in the absence of other reaction paths, undergoes hydrogen migration to afford the product (203). When the reaction is carried out... 

Photohydrogenation of various other organic substrates (i.e., 3-hexyne, 1,1-diphenylethylene, 3-pentanone, and butyraldehyde) was accomplished in similar photosystems in the presence of different heterogeneous metal colloids [123]. Also, organization of photosynthetic multiphase assemblies for photoinduced hydrogenation of water-insoluble alkenes and alkanes have been reported using multifunctional heterogeneous catalysts [124]. 

One of the chlorine atoms in phosphorus pentachloride appears to hold a unique position in that the products of the reaction mth indene, styrene, a-methylstyrene and 5 u.-diphenylethylene m cold benzene solution, suffer hydrolysis accompanied by intramolecular separation of the fifth chlorine atom as hydrogen chloride when treated with water. At much higher temperatures certain indones add on two chlorine atoms when treated with phosphorus pentachloride, this decisively indicating the fission PCI5 PClg + Clg. 

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