5342-87-0Relevant academic research and scientific papers
Titanium(IV) Chloride-Catalyzed Photoalkylation via C(sp3)-H Bond Activation of Alkanes
Yamane, Mina,Kanzaki, Yamato,Mitsunuma, Harunobu,Kanai, Motomu
supporting information, p. 1486 - 1490 (2022/03/01)
Despite the sophistication of C-H functionalization as one of the most powerful tools in organic synthesis, methodology for performing hydrogen-atom transfer of unactivated alkanes remains rather scarce. Herein, we describe chlorine radical-catalyzed C(sp3)-H photoalkylation using titanium(IV) chloride via a ligand-to-metal charge transfer process. Enabled by the unique properties of this abundant metal salt, the reaction not only effected the coupling of various alkanes with radical acceptors but also was shown to be applicable to direct photoalkylation of aromatic ketones.
Addition reactions of organic carbanion equivalents via hydrazones in water
Wang, Yi-Zhan,Liu, Qi,Cheng, Liang,Yu, Song-Chen,Liu, Li,Li, Chao-Jun
, (2021/01/11)
The addition of organometallic reagents to unsaturated bonds is one of the most powerful tools for carbon–carbon bond formations. Alkylation through organometallic reagents requires stoichiometric quantity of metal and tedious anhydrous operation in most cases. Here, we report “umpolung” nucleophilic additions of hydrazones to Michael acceptors, carbonyls and imines in water. Under the catalysis of ruthenium(II), the addition reactions could be carried out in pure water to provide various alkylation products in moderate to good yields.
Nucleophilic addition of benzylboronates to activated ketones
Hayes, Jacob C.,Hollerbach, Michael R.,Barker, Timothy J.
supporting information, (2019/12/27)
A method has been developed for the addition of benzylboronic acid pinacol ester to activated ketones including trifluoromethyl ketones in good yields. The use of DABCO as an additive was found to enhance the rate and efficiency of this reaction. In react
Carbon Dioxide-Mediated C(sp2)-H Arylation of Primary and Secondary Benzylamines
Kapoor, Mohit,Chand-Thakuri, Pratibha,Young, Michael C.
supporting information, p. 7980 - 7989 (2019/05/22)
C-C bond formation by transition metal-catalyzed C-H activation has become an important strategy to fabricate new bonds in a rapid fashion. Despite the pharmacological importance of ortho-arylbenzylamines, however, effective ortho-C-C bond formation of free primary and secondary benzylamines using PdII remains an outstanding challenge. Presented herein is a new strategy for constructing ortho-arylated primary and secondary benzylamines mediated by carbon dioxide (CO2). The use of CO2 with Pd is critical to allowing this transformation to proceed under relatively mild conditions, and mechanistic studies indicate that it (CO2) is directly involved in the rate-determining step. Furthermore, the milder temperatures furnish free amine products that can be directly used or elaborated without the need for deprotection. In cases where diarylation is possible, an interesting chelate effect is shown to facilitate selective monoarylation.
Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
supporting information, p. 5611 - 5615 (2019/08/01)
The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
Iron-Catalyzed Nucleophilic Addition Reaction of Organic Carbanion Equivalents via Hydrazones
Li, Chen-Chen,Dai, Xi-Jie,Wang, Haining,Zhu, Dianhu,Gao, Jian,Li, Chao-Jun
, p. 3801 - 3805 (2018/07/25)
Earth-abundant and well-defined iron complexes are found to be cheap and effective catalysts for a series of "umpolung" nucleophilic additions of hydrazones. The new catalytic system not only maintains the broad substrate scope of an earlier expensive ruthenium system but also attains chemoselectivity of different kinds of carbonyl groups. Furthermore, the iron catalyst enables this reaction at ambient temperature.
Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
Wang, Haining,Dai, Xi-Jie,Li, Chao-Jun
, p. 374 - 378 (2017/04/03)
Nucleophilic addition reactions of organometallic reagents to carbonyl compounds for carbon-carbon bond construction have played a pivotal role in modern chemistry. However, this reaction's reliance on petroleum-derived chemical feedstocks and a stoichiometric quantity of metal have prompted the development of many carbanion equivalents and catalytic metal alternatives. Here, we show that naturally occurring carbonyls can be used as latent alkyl carbanion equivalents for additions to carbonyl compounds, via reductive polarity reversal. Such 'umpolung' reactivity is facilitated by a ruthenium catalyst and diphosphine ligand under mild conditions, delivering synthetically valuable secondary and tertiary alcohols in up to 98% yield. The unique chemoselectivity exhibited by carbonyl-derived carbanion equivalents is demonstrated by their tolerance to protic reaction media and good functional group compatibility. Enantioenriched tertiary alcohols can also be accessed with the aid of chiral ligands, albeit with moderate stereocontrol. Such carbonyl-derived carbanion equivalents are anticipated to find broad utility in chemical bond formation.
Influence of the methyl group at C=C bridging bond of stilbene on the longest wavelength maximum in ultraviolet absorption spectra
Zhang, Yanxiu,Cao, Chao-Tun,Zhang, Jingyuan,Cao, Chenzhong
supporting information, (2017/09/30)
The compounds stilbenes XArCH=CHArY(XSBY) and 1,2-diphenylpropylenes XArC(Me)=CHArY(XSMBY) have bridging groups CH=CH and C(CH3)=CH, respectively, in which the C(CH3)=CH has a side-group CH3 at the carbon-carbon double bond. A series of XSMBY were synthesized, and their longest wavelength maximum λmax (nm) in ultraviolet absorption spectra were measured in this work. We investigated the change regularity of the νmax (cm-1, νmax?=?1/λmax) of XSMBY and compared it with that of XSBY. The results indicate that (1) there is no good linear relationship between the νmax of XSMBY and that of XSBY. (2) Because of the influence of the side-group CH3, in case of the same couple of groups X and Y, the λmax of XSMBY is shorter than that of XSBY, that is, it has a blue shift. (3) The cross-interaction between the side-group CH3 and Y has an important effect on the νmax of XSMBY, while the cross-interaction between the side-group CH3 and X has a little effect on the νmax and can be ignored. (4) The specific cross-interaction between X and Y has important effect on the νmax of XSMBY, whereas it has no important effect on the νmax of XSBY.
Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
Jereb, Marjan,Vra?i?, Dejan
, p. 747 - 762 (2018/01/17)
Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
Thermally Induced Carbohydroxylation of Styrenes with Aryldiazonium Salts
Kindt, Stephanie,Wicht, Karina,Heinrich, Markus R.
supporting information, p. 8744 - 8747 (2016/07/21)
The radical carbohydroxylation of styrenes with aryldiazonium salts has been achieved under mild thermal conditions. A broad range of aryldiazonium salts was tolerated, and the reaction principle based on a radical–polar crossover mechanism could be exten
