19179-60-3Relevant academic research and scientific papers
Evidence that Additions of Grignard Reagents to Aliphatic Aldehydes Do Not Involve Single-Electron-Transfer Processes
Otte, Douglas A. L.,Woerpel
, p. 3906 - 3909 (2015)
Addition of allylmagnesium reagents to an aliphatic aldehyde bearing a radical clock gave only addition products and no evidence of ring-opened products that would suggest single-electron-transfer reactions. The analogous Barbier reaction also did not pro
STEREOCHEMISTRY OF ELECTROREDUCTIONS OF BROMOCYCLOPROPANES 1-ASYMMETRIC ELECTROCHEMICAL SYNTHESIS BY REDUCTION AT A MERCURY CATHODE IN THE PRESENCE OF ADSORBED ALKALOIDS
Hazard, R.,Jaouannet, S.,Tallec, A.
, p. 93 - 102 (1982)
The electrochemical behaviours of 1-bromo-2,2-diphenylcyclopropane carboxylic acid, its methyl ester and 1,1-dibromo-2,2-diphenylcyclopropane are investigated in the presence of strongly adsorbed alkaloids: yohimbine, emetine, brucine, strychnine and methylstrichninium cations.The polarographic study evidences the existence of interactions between the alkyl bromides and nitrogen cations; these interactions make easier the 2e cleavage of the carbon-halogen bond.Whatever the alkaloid used, rather poor optical yields are obtained after electroreduction of monobromo compounds.On the contrary, notably optically active products are obtained from the dibromide derivative, but only when the inductor can act as a protonating species; 45percent optical yield can be achieved in the presence of emetine.The mechanism of asymmetric electrochemical synthesis is interpreted in terms of (i) preferential presentation of one of the two stereotopic faces of the substrate the mercury cathode, made chiral by the adsorption of the alkaloid and (ii) protonation by the acidic form of the inductor of the carbanion resulting from a 2e reduction.
Photochemical Carbene Transfer Reactions of Aryl/Aryl Diazoalkanes—Experiment and Theory**
Jana, Sripati,Pei, Chao,Empel, Claire,Koenigs, Rene M.
supporting information, p. 13271 - 13279 (2021/05/10)
Controlling the reactivity of carbene intermediates is a key parameter in the development of selective carbene transfer reactions and is usually achieved by metal complexes via singlet metal-carbene intermediates. In this combined experimental and computational studies, we show that the reactivity of free diaryl carbenes can be controlled by the electronic properties of the substituents without the need of external additives. The introduction of electron-donating and -withdrawing groups results in a significant perturbation of singlet triplet energy splitting of the diaryl carbene intermediate and of activation energies of consecutive carbene transfer reactions. This strategy now overcomes a long-standing paradigm in the reactivity of diaryl carbenes and allows the realization of highly chemoselective carbene transfer reactions with alkynes. We could show that free diaryl carbenes can be readily accessed via photolysis of the corresponding diazo compounds and that these carbenes can undergo highly chemoselective cyclopropenation, cascade, or C?H functionalization reactions. Experimental and theoretical mechanistic analyses confirm the participation of different carbene spin states and rationalize for the observed reactivity.
2,2-diphenylcyclopropyl compound and synthesis method thereof
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Paragraph 0025-0028, (2019/10/01)
The present invention provides a 2,2-diphenylcyclopropyl compound, which has a chemical name 2,2-diphenyl methyl cyclopropanecarboxylate compound, wherein the structure formula is defined in the specification, and the group R in the structure formula represents C1-C4 short-chain alkane, cycloalkane, halogenated alkane or halogenated cycloalkane. The present invention further provides a synthesis method of the 2,2-diphenylcyclopropyl compound, wherein the system method comprises: synthesizing Benzophenone hydrazone, synthesizing diphenyldiazomethane, and synthesizing the target product. According to the present invention, the three-membered ring of the 2,2-diphenyl methyl cyclopropanecarboxylate compound contains a chiral center, which can be used as a chiral precursor to introduce the chiral carbon atom into the reaction product so as to provide more possibility for the development of active compounds; and the synthesis method is simple, easy to operate, and suitable for industrial production.
Hypervalent-iodine(iii) oxidation of hydrazones to diazo compounds and one-pot nickel(ii)-catalyzed cyclopropanation
Liu, Haixuan,Wei, Yunyang,Cai, Chun
, p. 674 - 678 (2016/01/12)
A one-pot process for the catalytic cyclopropanation of various alkenes with unsubstituted hydrazones is described. Iodosobenzene (Ph = O) was found to be a competent oxidant of hydrazones to diazo compounds. Ni(OH)2 was chosen as an effective and cheap metal catalyst. The cyclopropane products can be generated efficiently (5 min-4 h) in moderate to good yields (42-91%) under mild (80°C) and neat conditions.
Total synthesis of cyclogalgravin and its dicarboxyl analog using sc(otf)3-mediated highly diastereoselective ring expansion of 1-(arylhydroxymethyl)cyclopropanecarboxylates
Sakuma, Daichi,Ito, Junki,Sakai, Ryo,Taguchi, Ryota,Nishii, Yoshinori
supporting information, p. 610 - 611 (2014/05/20)
The total synthesis of cyclogalgravin and its dicarboxyl analog was achieved by using the SmI2-promoted Reformatsky type reaction and Sc(OTf)3-mediated diastereoselective ring expansion as key steps.
1-[(E)-2-arylethenyl]-2,2-diphenylcyclopropanes: Kinetics and mechanism of rearrangement to cyclopentenes
Mulzer, Johann,Huisgen, Rolf,Arion, Vladimir,Sustmann, Reiner
experimental part, p. 1359 - 1388 (2011/10/09)
Kinetic measurements for the thermal rearrangement of 2,2-diphenyl-1-[(E)- styryl]cyclopropane (22a) to 3,4,4-triphenylcyclopent-1-ene (23a) in decalin furnished ΔHρm{{-{isom}^{ne }}}$=31.0±1.2kcal mol-1 and ΔSρm{{-{isom}^{ne }}}$=-6. 0±2.6e.u. The lowering of ΔHa‰ by 20kcal mol-1, compared with the rearrangement of the vinylcyclopropane parent, is ascribed to the stabilization of a transition structure (TS) with allylic diradical character. The racemization of (+)-(S)-22a proceeds with ΔHρm{{-{rac}^{ne }}}$=28.2±0.8kcal mol -1 and ΔSρm{{-{rac}^{ne }}}$=-5±2e.u., and is at 150° 106 times faster than the rearrangement. Seven further 1-(2-arylethenyl)-2,2-diphenylcyclopropanes 22, (E)- and (Z)-isomers, were synthesized and characterized. The (E)-compounds showed only modest substituent influence in their krac (at 119.4°) and kisom (at 159.3°) values. The lack of solvent dependence of rate opposes charge separation in the TS, but a linear relation of log krac with log p.r.f., i.e., partial rate factors of radical phenylations of ArH, agrees with a diradical TS. The ring-opening of the preponderant s-trans-conformation of 22 gives rise to the 1-exo-phenylallyl radical 26 that bears the diphenylethyl radical in 3-exo-position, and is responsible for racemization. The 1-exo-3-endo-substituted allylic diradical 27 arises from the minor s-gauche-conformation of 22 and is capable of closing the three- or the five-membered ring, 22 or 23, respectively. The discussion centers on the question whether the allylic diradical is an intermediate or merely a TS. Quantum-chemical calculations by Houk etal. (1997) for the parent vinylcyclopropane reveal the lack of an intermediate. Can the conjugation of the allylic diradical with three Ph groups carve the well of an intermediate? Copyright
Stereocontrol of intramolecular Diels-Alder reactions by an allylic diphenylcyclopropyl group
Tripoli, Regis,Cayzer, Tory N.,Willis, Anthony C.,Sherburn, Michael S.,Paddon-Row, Michael N.
, p. 2606 - 2616 (2008/03/12)
Intramolecular Diels-Alder reactions of ester-linked 1,3,8-nonatrienes carrying a diphenylcyclopropyl substituent attached to C1 proceed with high levels of stereoselectivity. The stereochemical outcomes of these reactions are explained by reference to B3
Cyclopropane formation via a simple barbier reaction in DMF
Oudeyer, Sylvain,Aaziz, Akima,Léonel, Eric,Paugam, Jean Paul,Nédélec, Jean-Yves
, p. 485 - 488 (2007/10/03)
Cyclopropanes are prepared in good yields via magnesium activation of polyhalomethyl compounds (dichlorodiphenylmethane, methyl trichloroacetate, α,α,α-trichlorotoluene, benzal chloride, benzal bromide) in the presence of activated olefins in DMF.
Cyclopropane formation by copper-catalysed indirect electroreductive coupling of activated olefins and activated α,α,α-trichloro or gem-dichloro compounds
Sengmany,Leonel,Paugam,Nedelec
, p. 533 - 537 (2007/10/03)
Cyclopropanes have been prepared in good yields by indirect electroreductive coupling of activated olefins and activated α,α,α-trichloro or gem-dichloro compounds (Cl3CCO2Me, PhCCl3, Ph2CCl2, PhCHCl2). This process, using a copper complex in catalytic amountss is convenient for the reagent couple activated olefin/activated polyhalide, whatever the reduction potential of each reagent relative to each other. The main advantage of our electrochemical process is that it does not require the use of hazardous, toxic, or not easily prepared reagents like diazocompounds or diazirines.
