104-83-6Relevant articles and documents
Thiourea-Mediated Halogenation of Alcohols
Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
, p. 12901 - 12911 (2020/11/26)
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
supporting information, p. 3403 - 3408 (2019/04/01)
The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
α-Diimine-Niobium Complex-Catalyzed Deoxychlorination of Benzyl Ethers with Silicon Tetrachloride
Parker, Bernard F.,Hosoya, Hiromu,Arnold, John,Tsurugi, Hayato,Mashima, Kazushi
supporting information, p. 12825 - 12831 (2019/10/19)
α-Diimine niobium complexes serve as catalysts for deoxygenation of benzyl ethers by silicon tetrachloride (SiCl4) to cleanly give two equivalents of the corresponding benzyl chlorides, where SiCl4 has the dual function of oxygen scavenger and chloride source with the formation of a silyl ether or silica as the only byproduct. The reaction mechanism has two successive trans-etherification steps that are mediated by the niobium catalyst, first forming one equivalent of benzyl chloride along with the corresponding silyl ether intermediate that undergoes the same reaction pathway to give the second equivalent of benzyl chloride and silyl ether.
A preparation method of the Pcad (by machine translation)
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Paragraph 0066-0068; 0077-0079, (2019/05/08)
The invention discloses a method for preparing chlorobenzaldehyde, monochlorotoluene to raw materials under the action of catalyst with chlorine to produce substitution reaction to obtain the mixture of chlorine phenmethyl chlorine and chlorine benzal chloride. To chlorine phenmethyl chlorine and chlorine benzal chloride mixture under the action of catalyst through hydrolytic reaction and air catalytic oxidation reaction to obtain the Pcad. The invention through the action of a catalyst reduces the reaction temperature of the substitution reaction, improves the selectivity of the substitution reaction, by hydrolysis reaction and air way of combining the catalytic oxidation reaction to improve the yield of chlorobenzaldehyde, through catalyst applied mechanically mode to reduce the hydrolysis reaction of the waste water. (by machine translation)
NMP-mediated chlorination of aliphatic alcohols with aryl sulfonyl chloride for the synthesis of alkyl chlorides
Zheng, Dagui,Mao, Liu-Liang,Zhu, Xian-Hong,Zhou, An-Xi
supporting information, p. 2793 - 2800 (2018/11/06)
NMP-mediated chlorination of aliphatic alcohols has been developed for the synthesis of alkyl chlorides. This facile, efficient and practical approach used simple and readily available aryl sulfonyl chlorides as the chlorination reagent for the construction of C–Cl bond in good to excellent yields with mild conditions and broad substrate scope.
Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
supporting information, p. 4541 - 4547 (2018/09/13)
Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
Ferric(III) Chloride Catalyzed Halogenation Reaction of Alcohols and Carboxylic Acids Using α,α-Dichlorodiphenylmethane
Lee, Chang-Hee,Lee, Soo-Min,Min, Byul-Hana,Kim, Dong-Su,Jun, Chul-Ho
supporting information, p. 2468 - 2471 (2018/04/25)
A new method for chlorination of alcohols and carboxylic acids, using α,α-dichlorodiphenylmethane as the chlorinating agent and FeCl3 as the catalyst, was developed. The method enables conversions of various alcohols and carboxylic acids to their corresponding alkyl and acyl chlorides in high yields under mild conditions. Particulary interesting is the observation that the respective alkyl bromides and iodides can be generated from alcohols when either LiBr or LiI are present in the reaction mixtures.
Highly selective halogenation of unactivated C(sp3)-H with NaX under co-catalysis of visible light and Ag@AgX
Liu, Shouxin,Zhang, Qi,Tian, Xia,Fan, Shiming,Huang, Jing,Whiting, Andrew
, p. 4729 - 4737 (2018/10/23)
The direct selective halogenation of unactivated C(sp3)-H bonds into C-halogen bonds was achieved using a nano Ag/AgCl catalyst at RT under visible light or LED irradiation in the presence of an aqueous solution of NaX/HX as a halide source, in air. The halogenation of hydrocarbons provided mono-halide substituted products with 95% selectivity and yields higher than 90%, with the chlorination of toluene being 81%, far higher than the 40% conversion using dichlorine. Mechanistic studies demonstrated that the reaction is a free radical process using blue light (450-500 nm), with visible light being the most effective light source. Irradiation is proposed to cause AgCl bonding electrons to become excited and electron transfer from chloride ions induces chlorine radical formation which drives the substitution reaction. The reaction provides a potentially valuable method for the direct chlorination of saturated hydrocarbons.
SNAr catalysis enhanced by an aromatic donor-acceptor interaction; Facile access to chlorinated polyfluoroarenes
Senaweera, Sameera,Weaver, Jimmie D.
, p. 7545 - 7548 (2017/07/12)
Selective catalytic SNAr reaction of polyfluoroaryl C-F bonds with chloride is shown. Stoichiometric TMSCl makes the reaction exergonic and allows catalysis, which involves ground state elevation of chloride, aromatic donor-acceptor interactions, and stabilization of the Meisenheimer complex. Traditional cross-coupling of the products is now possible and demonstrates the utility.
Mild Aliphatic and Benzylic Hydrocarbon C-H Bond Chlorination Using Trichloroisocyanuric Acid
Combe, Sascha H.,Hosseini, Abolfazl,Parra, Alejandro,Schreiner, Peter R.
, p. 2407 - 2413 (2017/03/11)
We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr4 reduced the reaction times considerably due to the formation of chain-carrying ·CBr3 radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.
