1.1- Diphenylcyclopropane

B. l,l-Diphenyl-2-bromo-Z-acetoxy- -j>ropene. A 250-ml. flask equipped with a condenser is charged with 17.6 g. (0.050 mole) of 1,1-dibromo-2,2-diphenylcyclopropane, 12.5g. (0.075 mole) of silver acetate [Acetic acid, silver(l +) salt] (Note 4), and 50 ml. of glacial acetic acid, then immersed in an oil bath at 100-120° for 24 hours (Note 5). After cooling, the mixture is diluted with 200 ml. of ether and filtered. The ethereal filtrate is washed with two 100-ml. portions of water, two 100-ml. portions of aqueous saturated sodium carbonate, and finally with two 100-ml. portions of water. After drying over anhydrous sodium sulfate, the ether is removed on a rotary evaporator. Distillation of the resulting residue under reduced pressure yields 12.0 g. (72%) of the product, b.p. 142-145° (0.15 mm.), 1.6020-1.6023 (Note 6). 

Corey and Chaykovsky114 found that the dimsyl anion reacts with benzophenone and benzaldehyde to afford the corresponding /S-hydroxysulfoxides 109 and 110. Thermal decomposition of these j3-hydroxysulfoxides was shown to give a, )3-unsaturated sulfoxides155 or olefins156,157. Thus, the reaction of dimsyl anion with benzophenone at 100 °C gave 1,1-diphenylethylene, diphenylmethane, 1,1-diphenylcyclopropane and diphenylacetaldehyde, besides 1, l-diphenyl-2-methylthioethylene156,157. 

Subsequently, a number of reactions at poly-L-valine coated carbon electrodes 237-243) gj.g reported to yield optically active products. Reductions, e.g. of citraconic acid or l,l-dibromo-2,2-diphenylcyclopropane as well as the oxidation of aryl-alkyl sulfides proceeded with chiral induction at such electrodes... 

A series of Ir(CO)Cl(PR3)2(r/2-3,3-diphenylcyclopropane) complexes (PR3 = PMe3, PMe2Ph, PMePh2, PEt3) is prepared according to reaction Scheme 35.561... 

Treatment of l,l-dichloro-2,3-diphenylcyclopropane 175a with Fp" results in reduction to the monochlorocyclopropane 176a rather than substitution. Under typical phase-transfer conditions, the reaction leads to the bridging... 

Casey extended his work (62) to conclude that a degree of chain-carrying character existed, as implied by diphenylcyclopropane formation. Chain character would be essential in a catalytic process as depicted in Eq. (25). 

Diphenylcyclopropane has been prepared in 24% yield by the Simmons-Smith reaction,2 in 78% yield by treatment of 3,3-diphenylpropyltrimethylammonium iodide with sodium or potassium amide,3 in 61% yield by reaction of 1,1-diphenyl-ethylene with dimethylsulfonium methylide,4 and in unspecified yields from 1,1-diphenylethylene by reaction with diazomethane followed by pyrolysis of the resulting pyrazoline or by reaction with ethyl diazoacetate followed by distillation of the corresponding acid over calcium oxide.5... 

Diphenylcyclopropane, 48, 75 Diphenylcyclopropenone, 47, 62 Diphenyldiacetylene, 46,39 Diphenyl disulfide, oxidation to methyl... 

Cathodic reduction of bicyclic gem-dibromocyclopropane in the presence of chlorotrimethylsilane provides the exo-silylated isomer selectively. With a sacrificial Mg anode the current efficiency can be increased by sonication as the anode acts additionally as a chemical reducing agent [358]. The 2e reduction of (5 )-(+)-l-bromo-l-carboxy-2,2-diphenylcyclopropane showed that the stereoselectivity at a Hg cathode was strongly determined by the supporting electrolyte cation. With NH4+, a preferential retention of configuration was observed, which increased with a more negative reduction potential. By contrast, a R4N+ cation gives rise to a major inversion, which increases with the bulkiness... 

Experimental Procedure 3.2.1. Cyclopropanation with an Iron Carbene Conqjlex 1,1-Diphenylcyclopropane [468]... 

Exposure of several methyl-substituted derivatives to y-radiolysis at 77 K in cryogenic matrices gave rise to a family of radical cations of the same structure type, some of which had been previously identified on the basis of CIDNP results. We begin with a discussion of the CIDNP investigations, since they preceded the ESR studies of all species but the prototype. The first CIDNP results attributed to a cyclopropane radical cation were observed during the photoreaction between 1,4-dicyanonaphthalene and cis-l,2-diphenylcyclopropane. However, the nature of the cyclopropane radical cation was characterized by CIDNP effects observed during the reaction of chloranil with cis- and /rans-l,2-diphenylcyclo-propane. ... 

Radical cations of the same general structure type as those derived from cis- and /ro/tf-diphenylcyclopropane have been established for numerous cyclopropane... 

Figures, h CIDNP spectra (cyclopropane resonances) observed during the electron transfer photoreaction of chloranil with c/s-1,2-diphenylcyclopropane (fop) and ben-zonorcaradiene (.bottom). The opposite signal directions observed for analogous protons in the two compounds constitute evidence that the two radical cations belong to two different structure types.

The imidazoline derivative cibenzohne (64) is a class I antiarrhythmic agent which has undergone clinical tnals in the United States with apparently satisfactory results It is synthesized by diphenylcyclopropananon of acrylonitnle by thermal carbene generation from diphenyldiazo methane (62) to give 1 cyano 2,2 diphenylcyclopropane (63) Reaction of this with ethylenedia mine tosylate completes the synthesis of ciben/oline (64) [221... 

It is suggested that the overall equilibrium is controlled by the last step all work on dihydrodiazepines shows that equilibria between the two tautomeric forms lies almost completely on the side of the conjugated form. In support of this it was shown that the bisanil of tra 5-2,3-diamino-1,1-diphenylcyclopropane does not rearrange thermally into a dihydrodia-zepine (65CB2701). In this instance, the last step is prevented by the presence of two phenyl groups at the 6-position. 

The same has been observed by Dodson and Klose in previous work where cis- and trans-1,2-diphenylcyclopropane were formed by pyrolysis of 2,3-diphenylthietane 1,1-dioxide at 230°C. Analogous results have been achieved by both photolysis and thermolysis of l-phenyl-2-benzoylthiethane 1,1-dioxide to a cis-trans mixture of l-phenyl-2-benzoylcyclopropane. ... 

Typical aromatic donors and acceptors undergo only minor geometry changes upon oxidation or reduction or upon population of the triplet state for these compounds, the reaction sequence ET followed by BET has no effect on the structure. If the triplet state or biradical belongs to a different stmcture type than radical ion and ground-state precursor, as is the case for cis- or fraui-1,2-diphenylcyclopropane (65) or norbornadiene (16) BET may occur with cleavage or for-mation of one or more C—C bonds. In such cases, the sequence ET-BET may... 

An extensive investigation of the photosensitized geometric isomerization of 1,2-diphenylcyclopropane has been performed.270,297... 

Photostationary cis/trans ratios vary with sensitizer structure in a manner not yet perfectly understood, and both the time required for attainment of a photostationary state and actual flash spectroscopic quenching rates indicate that energy transfer to diphenylcyclopropane is quite inefficient. Such should be the case if nonvertical energy transfer with the production of a biradical is occurring. When care is taken so that only the sensitizer absorbs light, only cis-trans isomerization is observed. Direct excitation of the cyclopropane produces 1,3-diphenyl-propene and 1-phenylindane as well.298... 

The nonvertical energy transfer observed between low energy sensitizers and diphenylcyclopropane may thus be similar to that observed with the stilbenes, namely a transition to a triplet level not able to be observed spectroscopically. 

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