- 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
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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
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p. 398 - 406
(2020/11/19)
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- Formamide Catalysis Facilitates the Transformation of Aldehydes into Geminal Dichlorides
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Herein, a novel method for the transformation of aldehydes into geminal dichlorides based on phthaloyl chloride as reagent and N -formylpyrrolidine as Lewis base catalyst is disclosed. Given the mild reaction conditions, the current protocol is distinguished by high levels of functional group compatibility and scalability and is operationally simple. The in situ formation of a Vilsmeier Haack reagent type intermediate is likely to be essential for this organocatalytic nucleophilic substitution reaction.
- Huy, Peter Helmut
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supporting information
p. 2474 - 2483
(2019/06/08)
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- Halogenation through Deoxygenation of Alcohols and Aldehydes
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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
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supporting information
p. 3061 - 3064
(2018/05/28)
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- Synthesis of Aryldihalomethanes by Denitrogenative Dihalogenation of Benzaldehyde Hydrazones
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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.
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supporting information
p. 2222 - 2228
(2017/07/07)
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- One-pot, selective and mild conversion of benzylic alcohols to gem -dichlorides using chlorodiphenylphosphine and 2,3-dichloro-5,6-dicyanobenzoquinone as a new and neutral system
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A mild and one-pot conversion of benzylic alcohols to their corresponding gem-dichlorides is reported for the first time using chlorodiphenylphosphine (ClPPh2) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in dichloromethane under neutral conditions and at room temperature. The present method can be efficiently used for preparation of gem-dichlorides even in the presence of some other functional groups with excellent chemoselectivity.
- Aghapour, Ghasem,Mohamadian, Samaneh
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p. 520 - 527
(2015/05/20)
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- Rasta resin-triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions
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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.
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supporting information
p. 1397 - 1405
(2014/07/22)
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- Phosphorus(V)-catalyzed deoxydichlorination reactions of aldehydes
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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.
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p. 8769 - 8776
(2013/09/23)
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- Chlorination of various substrates in subcritical carbon tetrachloride
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Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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experimental part
p. 2881 - 2888
(2010/06/16)
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- Facile conversion of aldehydes and ketones to gem-dichlorides using chlorodiphenylphosphine/N-chlorosuccinimide as a new and neutral system
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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
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experimental part
p. 4023 - 4035
(2009/04/11)
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- Conversion of aromatic aldehydes to gem-dichlorides using boron trichloride. A new highly efficient method for preparing dichloroarylmethanes
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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
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p. 579 - 581
(2007/10/03)
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- A simple and efficient procedure for the preparation of benzal chlorides and benzal bromides
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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
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p. 4015 - 4024
(2007/10/03)
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