Bibenzyl 1,2-diphenylethane

Two benzyl entities having opposite polarity condense with particular ease. It suffices to add half an equivalent of phenyllithium to bromobenzene to obtain bibenzyl (1,2-diphenylethane) quantitatively. " Applying this method to l,3-di(bromomethyl)-benzene opens a facile entry to the strained [2.2]metacyclophane (118 Scheme 1-84). ... 

The electrochemistry of cobalt-salen complexes in the presence of alkyl halides has been studied thoroughly.252,263-266 The reaction mechanism is similar to that for the nickel complexes, with the intermediate formation of an alkylcobalt(III) complex. Co -salen reacts with 1,8-diiodo-octane to afford an alkyl-bridged bis[Co" (salen)] complex.267 Electrosynthetic applications of the cobalt-salen catalyst are homo- and heterocoupling reactions with mixtures of alkylchlorides and bromides,268 conversion of benzal chloride to stilbene with the intermediate formation of l,2-dichloro-l,2-diphenylethane,269 reductive coupling of bromoalkanes with an activated alkenes,270 or carboxylation of benzylic and allylic chlorides by C02.271,272 Efficient electroreduc-tive dimerization of benzyl bromide to bibenzyl is catalyzed by the dicobalt complex (15).273 The proposed mechanism involves an intermediate bis[alkylcobalt(III)] complex. 

Dipicrylethane. See 2,4,6,2 T4, 6 -Hex a-nitro-sym-diphenylethane, Vol 2, p Blll-L, under Bibenzyl and Derivatives... 

In highly dilute mixtures of bibenzyl in tetralin (llj), (one part bibenzyl in 200-1000 parts tetralin) 1,1-diphenylethane is formed at a rate independent of dilution and roughly one-sixth of the rate found in pure bibenzyl. This implies that free-radical concentrations are independent of the concentration of free-radical initiators in sufficiently pure tetralin. 

The bibenzyls are characterized by the presence of one 1,2-diphenylethane structure in their molecules. Similar with the stilbene structures, there are hydroxyls, methyl, methoxy, prenyl, geranyl, etc., located in the structures of bibenzyls. Bibenzyls have been mainly isolated from bryophytes. In addition, a few compounds of this group were reported from the genera of Stemona, Dendrobium, and Polygonum. 

Diphenylethane (bibenzyl) 22 reacted with excess chlorosulfonic acid (4.5 equivalents) at room temperature (24 hours) to give the 4,4 -disulfonyl chloride 23 (79%) (Equation 8). 2... 

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