- One-pot, oxidative and selective conversion of benzylic silyl and tetrahydropyranyl ethers to gem-dichlorides using trichloroisocyanuric acid and triphenylphosphine as an efficient and neutral system
-
A one-pot and oxidative method is described for the first time for the conversion of benzylic trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers to gem-dichlorides using trichloroisocyanuric acid (TCCA) and triphenylphosphine (PPh3) in neutral media. Various theses substrates containing electron withdrawing or donating groups can be efficiently converted to their corresponding gem-dichlorides in good to excellent yields. The present method shows a high degree of chemoselectivity, and due to its one-pot nature is in accordance with green chemistry.
- Khadem Moghaddam, Roqayeh,Aghapour, Ghasem
-
p. 398 - 406
(2020/11/19)
-
- Revisiting the Perfluorinated Trityl Cation
-
Although ultimately not isolable for X-ray structural characterization, the free perfluorinated trityl cation was shown to be observable in neat triflic acid, which represents milder conditions than previous reports of this cation in “magic acid” or oleum. A triflate-bound species could be generated in organic solvents using stoichiometric amounts of triflic acid and was shown to be synthetically viable for hydride abstraction from Et3SiH. It was demonstrated that the para-position on the -C6F5 rings is the primary point of attack for decomposition of the cation.
- Delany, Eoghan G.,Kaur, Satnam,Cummings, Steven,Basse, Kristoffer,Wilson, David J. D.,Dutton, Jason L.
-
p. 5298 - 5302
(2019/03/11)
-
- Halogenation through Deoxygenation of Alcohols and Aldehydes
-
An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3Pa?O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.
- Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
-
supporting information
p. 3061 - 3064
(2018/05/28)
-
- Synthesis of Aryldihalomethanes by Denitrogenative Dihalogenation of Benzaldehyde Hydrazones
-
We report a denitrogenative dihalogenation reaction of phenyldiazomethanes in which the hypervalent iodine reagents PhICl2 and TolIF2 act as surrogates for elemental chlorine and fluorine. Halogen transfer from iodane to aryldiazomethane is described, as is a tandem oxidative dihalogenation reaction between iodane and hydrazone. This is the first use of non-α-stabilized diazo compounds in this reaction, which provided an efficient synthesis of aryldifluoromethane (ArCHF2) and aryldichloromethane (ArCHCl2) derivatives. (Figure presented.).
- Zhao, Zhensheng,Kulkarni, Kaivalya G.,Murphy, Graham K.
-
p. 2222 - 2228
(2017/07/07)
-
- Rasta resin-triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions
-
Heterogeneous polymer-supported triphenylphosphine oxides based on the rasta resin architecture have been synthesized, and applied as reagent precursors in a wide range of halogenation reactions. The rasta resin-triphenylphosphine oxides were reacted with either oxalyl chloride or oxalyl bromide to form the corresponding halophosphonium salts, and these in turn were reacted with alcohols, aldehydes, aziridines and epoxides to form halogenated products in high yields after simple purification. The polymersupported triphenylphosphine oxides formed as a byproduct during these reactions could be recovered and reused numerous times with no appreciable decrease in reactivity.
- Xia, Xuanshu,Toy, Patrick H.
-
supporting information
p. 1397 - 1405
(2014/07/22)
-
- Phosphorus(V)-catalyzed deoxydichlorination reactions of aldehydes
-
A phosphine oxide-catalyzed conversion of aldehydes into 1,1-dichlorides is reported. The reaction proceeds via a phosphorus(V)-catalysis manifold in which phosphine oxide turnover is achieved using oxalyl chloride as a consumable reagent. The new method is applicable to a range of aldehydes and, in combination with palladium-catalyzed reductive dimerization, gives rise to a new catalytic approach to the synthesis of stilbenes and a short formal synthesis of resveratrol.
- An, Jie,Tang, Xiaoping,Moore, Joshua,Lewis, William,Denton, Ross M.
-
p. 8769 - 8776
(2013/09/23)
-
- Facile synthesis of hypercrosslinked resin via photochlorination of p-xylene and succedent alkylation polymerization
-
A combination of photochlorination of p-xylene and succedent Friedel-Crafts alkylation polymerization was firstly used in the preparation of the hypercrosslinked adsorptive resin. The data of GC-MS and GC showed that a series of chlorizates were produced when p-xylene was photochlorinated. Hypercrosslinked resins could be synthesized by copolymerization, self-polymerization of chlorizates or post crosslinking reaction. The chemical structure and micromorphology of the porous resins were characterized by BET, FT-IR, SEM and elementary analysis (EA). The results showed that the novel adsorptive resins possess high BET surface near to 1038 m2/g and large pore volumes range from 0.5 to 1.2 cm3/g.
- Bai, Ling Ling,Zhou, Yong Hao,Wang, Xiu Li,Yuan, Si Guo,Wu, Xian Li
-
experimental part
p. 1115 - 1118
(2012/06/01)
-
- Facile conversion of aldehydes and ketones to gem-dichlorides using chlorodiphenylphosphine/N-chlorosuccinimide as a new and neutral system
-
Aldehydes and ketones are easily converted to their corresponding gem-dichlorides using a mixture of chlorodiphenylphosphine and N-chlorosuccinimide (ClPPh2/NCS) in dichloromethane under neutral conditions and at room temperature. Copyright Taylor & Francis Group, LLC.
- Aghapour, Ghasem,Afzali, Asieh
-
experimental part
p. 4023 - 4035
(2009/04/11)
-
- Nitrile ylide dimerization: Investigation of the carbene reactivity of nitrile ylides
-
A series of novel hexaaryl diazatrienes 5 ("nitrile ylide dimers") were synthesized directly from the corresponding diaryl ketimines 12 and dichlorotoluenes 13 in a facile one-pot synthesis. The carbene character of the nitrile ylides was investigated by varying the substituents on the aromatic ring adjacent to the carbene center. The isolation of the corresponding carbene dimers as stable crystalline materials with absorption maxima (λmax) from 363 to 422 nm was shown to be promoted by the absence of strongly electron-withdrawing substituents. The crystal structures indicate that the E-isomers were isolated when phenyl, 3-methylphenyl, and 3-chlorophenyl substituents are present at the carbene carbon; the Z-isomer was isolated when the more sterically hindered 2,4,6-trimethylphenyl substituent (Mes) is present. The 1H NMR spectra of the E-isomers demonstrate the nonequivalence of the aromatic rings, in which two of the aromatic rings of the imine moiety are pseudoaxial and the remaining aromatic rings are pseudoequatorial. The reactions proceed via the intermediate nitrile ylides 1 generated by the base-promoted 1,1-elimination of HCl from the intermediate chloroimine 14. The nitrile ylide was also generated by 1,3-elimination of HCl from the imidoyl chloride 18, confirming common pathways via the nitrile ylide as the dimer products obtained from these different routes were identical. The strongly electron-withdrawing 4-nitrophenyl substituent promotes the linear carbanion character of the 1,3-dipole and no dimer is formed.
- Fergus, Suzanne,Eustace, Stephen J.,Hegarty, Anthony F.
-
p. 4663 - 4669
(2007/10/03)
-
- Conversion of aromatic aldehydes to gem-dichlorides using boron trichloride. A new highly efficient method for preparing dichloroarylmethanes
-
The chlorination of aromatic aldehydes with boron trichloride in hexane under reflux conditions produces the corresponding dichloromethyl derivatives in excellent yields. (C) 2000 Elsevier Science Ltd.
- Kabalka, George W.,Wu, Zhongzhi
-
p. 579 - 581
(2007/10/03)
-
- A simple and efficient procedure for the preparation of benzal chlorides and benzal bromides
-
Benzal chlorides and benzal bromides were conveniently synthesized by reaction of aryl aldehydes with a Vilsmeier type reagent formed in situ by reduction of CCl4 or CBr4 in dimethylformamide (DMF) as solvent.
- Léonel, Eric,Paugam, Jean-Paul,Heintz, Monique,Nédélec, Jean-Yves
-
p. 4015 - 4024
(2007/10/03)
-
- New applications of tungsten hexachloride (WCl6) in organic synthesis. Halo-de-hydroxylation and dihalo-de-oxo-bisubstitution reactions
-
Tungsten hexachloride (WCl6) has been used for the halo-de-hydroxylation and dihalo-de-oxo-bisubstitution reactions of benzylic alcohols, benzaldehydes, acyloins, and epoxides to their chlorides, gem-dichlorides, vic-trichlorides, and vic-dichlorides respectively.
- Firouzabadi, Habib,Shiriny, Farhad
-
p. 14929 - 14936
(2007/10/03)
-
- A Willgerodt-Kindler Type Selenation of Dihalomethane Derivatives, Chloroform, and Sodium Trichloroacetate by Treating with a Base, Elemental Selenium, and an Amine
-
Treatment of dihalomethane derivatives, chloroform, or sodium trichloroacetate with elemental selenium in the presence of NaH and an excess amount of an amine gave the corresponding selenoamides, selenoureas, and bis(selenocarbamoyl) triselenides in modest yields. These products were afforded from reactive intermediates related to "selenocarbonyl halides" and "selenophosgenoids" generated by the reaction of dichloromethanide ions and trichloromethanide ion with N-alkylated aminopolyselenide species (R2N-(Se)n-).
- Shimada, Kazuaki,Yamaguchi, Minoru,Sasaki, Tohru,Ohnishi, Kenji,Takikawa, Yuji
-
p. 2235 - 2242
(2007/10/03)
-
- Process for the side-chain polyhalogenation of polyalkylaromatic hydrocarbons
-
A process for the selective side-chain halogenation of alkylaromatic hydrocarbons, consisting of reacting the hydrocarbon with an N-halogenoamine in the presence of a proton donor and a metal ion.
- -
-
-