Diphenyl adduct with

J 7i-Cycloadducts at the C4 — C5 azepine positions are also formed with 1,2,3,4-tetra-chloro-5,5-dimethoxycyclopentadiene260 261 and with hexachlorocyclopentadiene.261 The reactivity of ethyl l//-azepine-l-carboxylate towards cyclopentadienones has been studied in terms of frontier molecular orbital theory which predicts that dimethyl 2-oxo-4,5-diphenyl-cyclopenta-1 (5),3-diene-1,3-dicarboxylate (20) should be more reactive towards the 1/f-azepine than other more common cyclopcntadienone derivatives.262 In fact, in refluxing benzene, the cyclopentadienone and ethyl 1/f-azepine-l-carboxylate (1) form a mixture of the [4 + 2] n-endo,anti-adduct 22, produced by Cope rearrangement of the initially formed [2 + 4] 7T-adduct 21, and the c.w-adduct 23, a rare example of a [6 + 4] rc-cycloadduct. At room temperature, only the [6 + 4] adduct 23 and a small amount of the [2 + 4] adduct 21 are obtained, the latter rearranging to the [4 + 2] adduct 22 on warming.262 Other [4 + 2] 7r-adducts with cyclopentadienones have been prepared similarly.263... 

Whilst Lewis acids like SbCls or A1C13 form stable adducts with diphenyl cyclopropenone, from which the ketone can be regenerated unchanged208, trialkyl boranes effect a remarkable ring expansion to 2-phenyl indenone derivatives 309 containing an additional residue in the 3-position215. ... 

C6HS)2C=N—B(CH3)2 was obtained by pyrolysis of the adduct of diphenyl-ketimine with trimethylborane °) according to Eq. (8) ... 

The ligand 2-allylpyridine is reported to form chelate complexes with copper(I) chloride, silver nitrate and platinum(II) chloride (29). Diphenyl vinylphosphine also forms stable 1 1 and 2 1 adducts with silver nitrate in which both the phosphorous and the double bond are thought to be coordinated to silver (30). 

Like isoconjugate mesomeric betaines, which have been discussed in preceding sections, phthalazinium-l-olates (196) give 1,3-dipolar adducts with acetylenes. Thermally induced isomerization reactions of these adducts (255) make them of special interest. The A-methyl derivative and diphenyl-... 

Antimony(III) halides are Lewis adds and will form adducts with Lewis bases. An example is provided by Lipka and Mootz,149 who prepared an adduct of diphenyl with SbCl3, 2SbCl3-PhPh (51). A molecule of SbCl3 is bonded to each of the biphenyl rings, but there are two differently bonded antimony atoms. One which forms the chain is six-coordinate there are three chlorine atoms at a normal distance, 2.36 A (av), and two at the longer distances of 3.443... 

Only dimethyl acetylenedicarboxylate adducts with 2,3,4,5-tetraphenylsiloles are isolable but not those with 2,5-diphenyl- or 3,4-dimethylsiloles. The corresponding adducts with C-phenylated germoles64,135 or a C-tetraphenylstannole136 are not isolable either. 

Rafikov et al. [35] describe a correlation between the electron-donating capacity of substituted benzenes and the efficiency of adduct formation with maleic anhydride. This is only valid if similar compounds are compared. The ionization potentials of benzene and toluene are 9.246 and 8.820 eV, respectively the yields of adduct formation are 70% and 30%, respectively. In the series of halogenobenzenes, the ionization potentials are as follows fluorobenzene, 9.195 eV chlorobenzene, 9.080 eV bromobenzene, 9.030 eV the yields of adducts are 7%, 2%, and <1%, respectively. Anisole and diphenyl ether, with ionization potentials of 8.220 and 8.090 eV, respectively, do not give adducts with maleic anhydride. It thus seems that an increase in the electron-donating capacity of the benzene derivative leads to a decrease in the yield of photoadducts. 

New quasiphosphonium halides derived from neopentyl diphenyl-phosphinite and dineopentyl phenylphosphonite are reported and it is shown that the attachment of phenyl groups to phosphorus provides enhanced stability. The products, Ph2P(0R)MeX (X = Cl, Br, or I) and PhP(0R)2MeX (X = Br or I) (R = Me3CCH2), are resistant to moist air and can be handled in the open laboratory for the purpose of X-ray diffraction studies (1). The rate of initial reaction between the ester and an alkyl halide increases with the number of phenyl substituents on phosphorus from the diphenyl-phosphinite an adduct with chloromethane can be prepared. 

Complexes with 1,3-dienes. The reaction of activated Mg (11, 307) in THF at 25° with (E,E)-1,4-diphenyl-1,3-butadiene results in the deep red complex (1,4-diphenyl-1,2-butene-1,4-diylmagnesium). This halide-free bismagnesium reagent (1) forms a 1,4-adduct with a, co-dibromoalkanes, which undergoes intramolecular... 

The same salt from acetylene afforded similarly adducts with furan and 1,3-diphenyl i sobenzofuran. A number of alkynyl iodonium salts underwent also [2 + 3] cycloaddition with dipolarophiles such as a-diazocarbonyl compounds, nitrile oxides, etc., allowing the preparation of iodonium salts with an alkenyl or a heterocyclic moiety [7],... 

Azine approach. 1 -Pyridinimines undergo 1,3-dipolar cycloaddition reactions with thiones. In the reaction between 2-isoquinolinimine and carbon disulfide the mesoionic thiadiazole (716) is formed the formation of (716) involves a secondary dehydrogenation of the initial adduct. With diphenyl thionocarbonate, phenoxy group expulsion is succeeded by cyclization leading to the adduct (717) (62TL387). 

Tosylamination ofalkenes, The reaction of diphenyl disulfide with chloramine-T in acetone gives, in 91% yield, an adduct of the composition (C6HsSSC6H5)(NTs)2 shown to have the structure (1) by virtue of subsequent reactions with alkenes. Thus it reacts with cyclohexene to give (2), which was reduced by sodium borohydride to (3), whose structure was established by an independent synthesis. 

Perfluoroalkylselenenylation of alkenes in the reaction of diphenyl diselenide with sodium borohydride followed by perfluoroalkyl halides is relatively stereoselective since a mixture of irans- and cw-adducts is obtained for both cyclohexene [X = CII2 d.r. (trans/cis) 75 25] and dihydropyran [X = O d.r. (transjeis) 73 27]... 

Engman reported that the acetoxyselenenylation of alkenes could be better carried out with PhSeBr in acetic acid in the presence of acetic anhydride and KNO3 [40]. In the case of terminal olefins the addition proceeds with poor regio-control. However, when the chloroform solution of the two products was treated with catalytic amounts of boron trifluoride etherate, isomerization takes place and the anti-Markovnikov adduct was transformed into the Markovnikov product. The acetoxyselenenylation of alkenes can be cleanly effected also by oxidation of diphenyl diselenide with iodobenzene diacetate in acetonitrile [22]. 

An attempted synthesis of thiete by thermolysis (300°) of a Diels-Alder adduct with anthracene was unsuccessful, no doubt because of the thermal instability of thiete.Thiete derivative 215 was obtained by other methods, and structure 217 was suggested as an intermediate in the desulfurization of 216. The unusual dithiolactone 218b is formally derived from a cycloaddition of carbon disulfide with acetylene 218a. " A 2-substituted-3,4-diphenyl-2H-thiete is obtained by treatment of the ylide, 8-methyl-1,3-diphenyldibenzo [e, h]-8-thiazulene, with diphenylcyclo-propenethione. 2-Methoxy-3,4-diphenyl-2H-thiete is one of several products obtained on photolysis of diphenylcyclopropenethione in methanol. ... 

In connection with the formation of modern electronic materials such as gallium phosphide, there have been a number of fundamental studies of the course of pyrolysis of t-butyl-phosphine.. in a related area, adducts of diphenyl-phosphine with trialkylgallium acceptors have been described. ... 

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