- Electrochemical radical reactions of alkyl iodides: a highly efficient, clean, green alternative to tin reagents
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An electrochemical ‘redox-relay’ system has been developed which allows the generation of C-centered radicals. Intermolecular ‘tin-like’ radical reactions can subsequently be conducted under the most benign of conditions. The yields and efficiency of the processes are competitive and even superior in most cases to comparable conditions with tributyltin hydride. The use of air and electricity as the promotor (instead of a tin or other reagent) combined with the aqueous reaction media make this a clean and ‘green’ alternative to these classic C-C bond forming processes.
- Li, Diyuan,Ma, Tsz-Kan,Scott, Reuben J.,Wilden, Jonathan D.
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p. 5333 - 5338
(2020/06/04)
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- Stereoselective synthesis of α-methyl and α-alkyl ketones from esters and alkenes: Via cyclopropanol intermediates
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Alkenes bearing a stereocenter in the allylic position were found to undergo Kulinkovich hydroxycyclopropanation with good diastereoselectivity. For the isomerization of the resulting cyclopropanols to diastereomerically enriched α-methyl ketones, a new mild regioselective method has been developed. A sequence of stereoselective cyclopropanation and cyclopropanol ring opening was successfully employed for the construction of the C20 stereocenter in steroids.
- Barysevich, Maryia V.,Kazlova, Volha V.,Kukel, Aliaksandr G.,Liubina, Aliaksandra I.,Hurski, Alaksiej L.,Zhabinskii, Vladimir N.,Khripach, Vladimir A.
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supporting information
p. 2800 - 2803
(2018/03/21)
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- Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination
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A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.
- Dakarapu, Udaya Sree,Bokka, Apparao,Asgari, Parham,Trog, Gabriela,Hua, Yuanda,Nguyen, Hiep H.,Rahman, Nawal,Jeon, Junha
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supporting information
p. 5792 - 5795
(2015/12/11)
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- Catalytic functionalization of methane and light alkanes in supercritical carbon dioxide
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The development of catalytic methods for the effective functionalization of methane yet remains a challenge. The best system known to date is the so-called Catalytica Process based on the use of platinum catalysts to convert methane into methyl bisulfate with a TOF rate of 10-3 s. In this contribution, we report a series of silver complexes containing perfluorinated tris(indazolyl)borate ligands that catalyze the functionalization of methane into ethyl propionate upon reaction with ethyl diazoacetate (EDA) by using supercritical carbon dioxide (scCO2) as the reaction medium. The employment of this reaction medium has also allowed the functionalization of ethane, propane, butane, and isobutane.
- Fuentes, M. Angeles,Olmos, Andrea,Caballero, Ana,Perez, Pedro J.,Munoz, Bianca K.,Jacob, Kane,Etienne, Michel,Gonzalez-Nunez, M. Elena,Mello, Rossella,Asensio, Gregorio
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supporting information
p. 11013 - 11018,6
(2015/01/07)
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- Ultrasound in organic syntheses. 19. Further studies on the conjugate additions to electron deficient olefins in aqeuous media
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Alkyl halides add smoothly to a variety of olefinic bonds conjugated with electron withdrawing groups, in the presence of zinc-copper couple. Sonication enhances the efficiency of the process, which takes place in aqeuous media following, most probably, a radical pathway.
- Dupuy,Petrier,Sarandeses,Luche
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p. 643 - 651
(2007/10/02)
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- IONIC DENITROHYDROGENATION OF α-NITRO OR β-NITRO SULFIDES WITH TRIETHYLSILANE
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The nitro groups of α-nitro or β-nitro sulfides are replaced by hydrogen on treatment with triethylsilane in the presence of Lewis acid.
- Ono, Noboru,Hashimoto, Toshihiro,Jun, Tuo Xiao,Kaji, Aritsune
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p. 2277 - 2280
(2007/10/02)
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- DENITROHYDROGENATION OF ALIPHATIC NITRO COMPOUNDS AND A NEW USE OF ALIPHATIC NITRO COMPOUNDS AS RADICAL PRECURSORS
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Aliphatic nitro groups are replaced by hydrogen on treatment with tributyltin hydride which proceeds via free radical chain processes.As the nitro group is selectively denitrated and other reducible groups are not affected with tributyltin hydride, this reaction can be used as a method for removing the nitro group from polyfunctional compounds.The radical intermediates generated via denitration can be also used for the carbon-carbon bond forming reactions.
- Ono, Noboru,Miyake, Hideyoshi,Kamimura, Akio,Hamamoto, Isami,Tamura, Rui,Kaji, Aritsune
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p. 4013 - 4024
(2007/10/02)
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- AN IMPROVED PROCEDURE FOR HYDROSILATION OF α,β-UNSATURATED ESTERS AND AN EXTENSION TO CONJUGATED DIENE ESTERS
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Treatment of α,β-unsaturated esters with triethylsilane in benzene in the presence of a catalytic amount of tris(triphenylphosphine)rhodium chloride at room temperature followed by chromatography on silica gel give rise to the corresponding saturated esters.Under similar conditions, fully conjugated diene esters were reduced to the dihydrolevel to give β,γ- or γ,δ-unsaturated esters depending upon the substitution pattern of the starting substrate.
- Liu, Hsing-Jang,Ramani, Brahma
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p. 965 - 972
(2007/10/02)
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