4830-95-9Relevant academic research and scientific papers
Cu-Catalyzed Site-Selective Benzylic Chlorination Enabling Net C–H Coupling with Oxidatively Sensitive Nucleophiles
Lopez, Marco A.,Buss, Joshua A.,Stahl, Shannon S.
supporting information, p. 597 - 601 (2022/01/20)
Site-selective chlorination of benzylic C–H bonds is achieved using a CuICl/bis(oxazoline) catalyst with N-fluorobenzenesulfonimide as the oxidant and KCl as a chloride source. This method exhibits higher benzylic selectivity, relative to estab
Hydrohalogenation of Unactivated Alkenes Using a Methanesulfonic Acid/Halide Salt Combination
Bertrand, Xavier,Chabaud, Laurent,Paquin, Jean-Fran?ois,Paquin, Pascal
, (2021/12/02)
The hydrochlorination, hydrobromination, and hydroiodination of unactivated alkenes using methanesulfonic acid and inorganic halide salts (CaCl2, LiBr, LiI) in acetic acid are reported. This approach uses readily available and inexpensive reagents to prov
Lewis Base Catalysis Enables the Activation of Alcohols by means of Chloroformates as Phosgene Substitutes
Zoller, Ben,Stach, Tanja,Huy, Peter H.
, p. 5637 - 5643 (2020/09/21)
Nucleophilic substitutions (SN) are typically promoted by acid chlorides as sacrificial reagents to improve the thermodynamic driving force and lower kinetic barriers. However, the cheapest acid chloride phosgene (COCl2) is a highly toxic gas. Against this background, phenyl chloroformate (PCF) was discovered as inherently safer phosgene substitute for the SN-type formation of C?Cl and C?Br bonds using alcohols. Thereby, application of the Lewis bases 1-formylpyrroldine (FPyr) and diethylcyclopropenone (DEC) as catalysts turned out to be pivotal to shift the chemoselectivity in favor of halo alkane generation. Primary, secondary and tertiary, benzylic, allylic and aliphatic alcohols are appropriate starting materials. A variety of functional groups are tolerated, which includes even acid labile moieties such as tert-butyl esters and acetals. Since the by-product phenol can be isolated, a recycling to PCF with inexpensive phosgene would be feasible on a technical scale. Eventually, a thorough competitive study demonstrated that PCF is indeed superior to phosgene and other substitutes.
Radical Deoxychlorination of Cesium Oxalates for the Synthesis of Alkyl Chlorides
Su, Justin Y.,Grünenfelder, Denise C.,Takeuchi, Kohei,Reisman, Sarah E.
supporting information, p. 4912 - 4916 (2018/08/24)
A radical deoxychlorination of cesium oxalates has been developed for the preparation of hindered secondary and tertiary alkyl chlorides. The reaction tolerates a number of functional groups, including ketones, alcohols, and amides, and provides complementary reactivity to standard deoxychlorination reactions proceeding by heterolytic mechanisms. Preliminary studies demonstrate that the developed conditions can also be applied to deoxybromination and deoxyfluorination reactions.
Ti-Catalyzed Radical Alkylation of Secondary and Tertiary Alkyl Chlorides Using Michael Acceptors
Wu, Xiangyu,Hao, Wei,Ye, Ke-Yin,Jiang, Binyang,Pombar, Gisselle,Song, Zhidong,Lin, Song
supporting information, p. 14836 - 14843 (2018/11/10)
Alkyl chlorides are common functional groups in synthetic organic chemistry. However, the engagement of unactivated alkyl chlorides, especially tertiary alkyl chlorides, in transition-metal-catalyzed C-C bond formation remains challenging. Herein, we describe the development of a TiIII-catalyzed radical addition of 2° and 3° alkyl chlorides to electron-deficient alkenes. Mechanistic data are consistent with inner-sphere activation of the C-Cl bond featuring TiIII-mediated Cl atom abstraction. Evidence suggests that the active TiIII catalyst is generated from the TiIV precursor in a Lewis-acid-assisted electron transfer process.
Halogenation through Deoxygenation of Alcohols and Aldehydes
Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
supporting information, p. 3061 - 3064 (2018/05/28)
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.
Desulfurative Chlorination of Alkyl Phenyl Sulfides
Canestrari, Daniele,Lancianesi, Stefano,Badiola, Eider,Strinna, Chiara,Ibrahim, Hasim,Adamo, Mauro F. A.
, p. 918 - 921 (2017/02/26)
The chlorination of readily available secondary and tertiary alkyl phenyl sulfides using (dichloroiodo)benzene (PhICl2) is reported. This mild and rapid nucleophilic chlorination is extended to sulfa-Michael derived sulfides, affording elimination-sensitive β-chloro carbonyl and nitro compounds in good yields. The chlorination of enantioenriched benzylic sulfides to the corresponding inverted chlorides proceeds with high stereospecificity, thus providing a formal entry into enantioenriched chloro-Michael adducts. A mechanism implying the formation of a dichloro-λ4-sulfurane intermediate is proposed.
Isolable and Readily Handled Halophosphonium Pre-reagents for Hydro- and Deuteriohalogenation
Schevenels, Florian T.,Shen, Minxing,Snyder, Scott A.
supporting information, p. 6329 - 6337 (2017/09/12)
Although the addition of acid halides across olefins is well-studied, limitations remain with a number of substrate classes that possess leaving groups, polyunsaturation, and acid-sensitive moieties, particularly polyenes prone to cyclization. The process is also challenging when conducted on a small scale, and moreover, methods for the addition of their deuterated counterparts typically require special techniques, especially when control of stoichiometry is required. Herein is described a readily synthesized and handled reagent class which can accomplish the controlled and selective Markovnikov addition of both HCl and HBr across several alkene classes under mild reaction conditions tolerant of diverse functionality. The process is particularly valuable on a laboratory scale, and direct comparisons to other methods are provided. As a result of in-depth mechanistic studies seeking to understand how these novel tools work and the active species behind their efficacy, the means to easily add DCl and DBr using a controlled amount of D2O was discovered along with the critical role of hydrolysis in leading to active hydrohalogenation species.
Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
Ajvazi, Njomza,Stavber, Stojan
supporting information, p. 2430 - 2433 (2016/05/19)
A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
Amines vs. N-Oxides as Organocatalysts for Acylation, Sulfonylation and Silylation of Alcohols: 1-Methylimidazole N-Oxide as an Efficient Catalyst for Silylation of Tertiary Alcohols
Murray, James I.,Spivey, Alan C.
, p. 3825 - 3830 (2016/01/25)
A comparison of the relative catalytic efficiencies of Lewis-basic amines vs. N-oxides for the acylation, sulfonylation and silylation of primary, secondary and tertiary alcohols is reported. Whilst the amines are generally superior to the N-oxides for acylation, the N-oxides are superior for sulfonylation and silylation. In particular, 1-methylimidazole N-oxide (NMI-O) is found to be a highly efficient catalyst for sulfonylation and silylation reactions. To the best of our knowledge, NMI-O is the first amine or N-oxide Lewis basic organocatalyst capable of promoting the efficient silylation of tert-alcohols in high yield with low catalyst loading under mild reaction conditions.
