- Enhancing the leaving group ability of alkyl fluorides: I/F exchange reactions mediated by LiI
-
The carbon–fluorine (C–F) bond is one of the strongest bonds in organic chemistry and generally inert toward nucleophilic substitution reactions. To overcome the relative inertness of the C–F bond, this work focused on the ability of simple lithium salts
- Zerban, Jensen J.,Bagnall, Brody,Davis, Todd A.
-
supporting information
(2022/01/28)
-
- Regiodivergent Conversion of Alkenes to Branched or Linear Alkylpyridines
-
Herein we report a practical protocol for the visible-light-induced regiodivergent radical hydropyridylation of unactivated alkenes using pyridinium salts. This approach provides a unified synthetic platform to control the regioselectivity of the synthesis of linear or branched C4-alkylated pyridines. A remarkable selectivity switch from the anti-Markovnikov to the Markovnikov product can be achieved by the addition of tetrabutylammonium bromide. The versatility of this protocol is further demonstrated based on the late-stage functionalization in pharmaceuticals.
- Kim, Minseok,Shin, Sanghoon,Koo, Yejin,Jung, Sungwoo,Hong, Sungwoo
-
supporting information
p. 708 - 713
(2022/01/20)
-
- One-Pot Deoxygenation and Substitution of Alcohols Mediated by Sulfuryl Fluoride
-
Sulfuryl fluoride is a valuable reagent for the one-pot activation and derivatization of aliphatic alcohols, but the highly reactive alkyl fluorosulfate intermediates limit both the types of reactions that can be accessed as well as the scope. Herein, we report the SO2F2-mediated alcohol substitution and deoxygenation method that relies on the conversion of fluorosulfates to alkyl halide intermediates. This strategy allows the expansion of SO2F2-mediated one-pot processes to include radical reactions, where the alkyl halides can also be exploited in the one-pot deoxygenation of primary alcohols under mild conditions (52-95% yield). This strategy can also enhance the scope of substitutions to nucleophiles that are previously incompatible with one-pot SO2F2-mediated alcohol activation and enables substitution of primary and secondary alcohols in 54-95% yield. Chiral secondary alcohols undergo a highly stereospecific (90-98% ee) double nucleophilic displacement with an overall retention of configuration.
- Epifanov, Maxim,Mo, Jia Yi,Dubois, Rudy,Yu, Hao,Sammis, Glenn M.
-
supporting information
p. 3768 - 3777
(2021/03/01)
-
- Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes
-
The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.
- Zeng, Chaoyuan,Shen, Guoli,Yang, Fan,Chen, Jingchao,Zhang, Xuexin,Gu, Cuiping,Zhou, Yongyun,Fan, Baomin
-
supporting information
p. 6859 - 6862
(2018/10/25)
-
- Stereospecific Electrophilic Fluorination of Alkylcarbastannatrane Reagents
-
We report the use of isolable primary and secondary alkylcarbastannatrane nucleophiles in site-specific fluorination reactions. These reactions occur without the need for transition metal catalysis or in situ activation of the nucleophile. In the absence of the carbastannatrane backbone, alkyltin nucleophiles exhibit no activity towards fluorination. When enantioenriched alkylcarbastannatranes are employed, fluorination occurs predominately via a stereoinvertive mechanism to generate highly enantioenriched alkyl fluoride compounds. These conditions can also be extended to stereospecific chlorination, bromination, and iodination reactions.
- Ma, Xinghua,Diane, Mohamed,Ralph, Glenn,Chen, Christine,Biscoe, Mark R.
-
supporting information
p. 12663 - 12667
(2017/09/11)
-
- Method for the Preparation of Iodoalkanes
-
The present invention relates to an atom economic procedure of preparing iodoalkanes by hydroiodination of alkenes. In particular the present method features the generation of anhydrous hydrogen iodide from atomic hydrogen and iodine in situ by using transition metal precursor and phosphine ligandcatalyst.
- -
-
Paragraph 0036
(2017/08/07)
-
- Catalytic Access to Alkyl Bromides, Chlorides and Iodides via Visible Light-Promoted Decarboxylative Halogenation
-
Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.
- Candish, Lisa,Standley, Eric A.,Gómez-Suárez, Adrián,Mukherjee, Satobhisha,Glorius, Frank
-
supporting information
p. 9971 - 9974
(2016/07/19)
-
- Iron-catalyzed cross-coupling of unactivated secondary alkyl thio ethers and sulfones with aryl grignard reagents
-
The first systematic investigation of unactivated aliphatic sulfur compounds as electrophiles in transition-metal-catalyzed cross-coupling are described. Initial studies focused on discerning the structural and electronic features of the organosulfur substrate that enable the challenging oxidative addition to the C(sp3)-S bond. Through extensive optimization efforts, an Fe(acac)3-catalyzed cross-coupling of unactivated alkyl aryl thio ethers with aryl Grignard reagents was realized in which a nitrogen "directing group" on the S-aryl moiety of the thio ether served a critical role in facilitating the oxidative addition step. In addition, alkyl phenyl sulfones were found to be effective electrophiles in the Fe(acac) 3-catalyzed cross-coupling with aryl Grignard reagents. For the latter class of electrophile, a thorough assessment of the various reaction parameters revealed a dramatic enhancement in reaction efficiency with an excess of TMEDA (8.0 equiv). The optimized reaction protocol was used to evaluate the scope of the method with respect to both the organomagnesium nucleophile and sulfone electrophile.
- Denmark, Scott E.,Cresswell, Alexander J.
-
p. 12593 - 12628
(2014/01/17)
-
- Selective C-F bond activation: Substitution of unactivated alkyl fluorides using YbI3
-
F makes the break: The carbon-fluorine single bond is quite strong, thus making aliphatic C-F bond scission unusually challenging. A new methodology utilizing YbI3 leads to the conversion of a C-F bond into a C-I bond, and is compatible with various functional groups. The reaction is exceptionally selective towards alkyl fluorides and proceeds under mild conditions. Copyright
- Traeff, Annika M.,Janjetovic, Mario,Ta, Linda,Hilmersson, Goeran
-
supporting information
p. 12073 - 12076
(2013/12/04)
-
- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
-
Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
-
supporting information
p. 2692 - 2698,7
(2012/12/12)
-
- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
-
Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener. Georg Thieme Verlag KG Stuttgart · New York.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
-
supporting information
p. 2692 - 2698
(2013/01/15)
-
- An intriguing hydroiodination of alkenes and alkynes with titanium tetraiodide
-
Olefins and acetylenes were hydroiodinated with titanium tetraiodide to give alkyl iodides, vinyl iodides, and alkyl diiodides in good yields. In the presence of acetals, the reaction gave intriguing C-C bond-forming products. Georg Thieme Verlag Stuttgart.
- Shimizu, Makoto,Toyoda, Tadahiro,Baba, Toru
-
p. 2516 - 2518
(2007/10/03)
-
- A mild, phosphine-free method for the conversion of alcohols into halides (Cl, Br, I) via the corresponding O-alkyl isoureas
-
A novel procedure for the conversion of primary and secondary alcohols into the corresponding alkyl chlorides, bromides and iodides is described. The transformation is high-yielding in the case of chlorides and bromides, tolerates a range of functional groups, and does not rely on the use of phosphines.
- Li, Zhengning,Crosignani, Stefano,Linclau, Bruno
-
p. 8143 - 8147
(2007/10/03)
-
- Direct conversion of carbonyl compounds into organic halides: Indium(III) hydroxide-catalyzed deoxygenative halogenation using chlorodimethylsilane
-
The reaction of carbonyls and chlorodimethylsilane was effectively catalyzed by indium(III) hydroxide and afforded the corresponding deoxygenative chlorination products, in which the carbonyl carbon accepted two nucleophiles (H and Cl) with releasing oxygen. Only In(OH)3 catalyzed the reaction, and typical Lewis acids such as TiCl4, AlCl3, and BF3·OEt2 showed no catalytic activity. The reaction mechanism of this deoxygenative chlorination includes initial hydrosilylation followed by chlorination. Other nucleophiles such as allyl or iodine were available for this methodology. The moderate Lewis acidity of indium catalyst enabled chemoselective reaction, and therefore ester, nitro, cyano, or halogen groups were not affected during the reaction course. Copyright
- Onishi, Yoshiyuki,Ogawa, Daigo,Yasuda, Makoto,Baba, Akio
-
p. 13690 - 13691
(2007/10/03)
-
- Diiodosilane. 2. A Multipurpose Reagent for Hydrolysis and Reductive Iodination of Ketals, Acetals, Ketones, and Aldehydes
-
The reaction patterns of diiodosilane (SiH2I2, DIS) with ketals, acetals, ketones, and aldehydes were explored.The reagent may be used for mild cleavage of ketals and acetals either hydrolytically to give the parent carbonyl functionality or reductively to produce the corresponding alkyl iodide.At low temperatures (-42 deg C) and short reaction times (few minutes), catalytic amounts (5-10 molpercent) of DIS provide clean deprotection of various ketals and acetals to yield ketones and aldehydes, with no apparent reduction of the latter.At temperatures above 0 deg C, DIS effectively reduces ketals and acetals to iodoalkanes.This reduction is quite general both with respect to ketals and acetals and unprotected ketones and aldehydes.Reaction rates, however, are strikingly dependent on the substrate, with the following tendencies: (a) aromatic functionalities are generally reduced much faster than their aliphatic analogues; (b) ketals and acetals are rapidly reduced to the corresponding iodoalkanes, while free aldehydes, and particularly ketones, are essentially inert under the reaction conditions (but can be significantly activated by catalytic amounts of iodine); (c) dimethyl ketals form the parent ketones preferentially, while all other ketals, including diethyl ketals and dioxolanes, are reduced to iodoalkanes.
- Keinan, E.,Perez, D.,Sahai, M.,Shvily, R.
-
p. 2927 - 2938
(2007/10/02)
-