- Synthesis and properties of novel dialkylaminocarbenium salts
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Novel dialkylaminocarbenium salts with metallocomplex counter ions were prepared by the reaction of phosgene with either DMF or tetramethylurea in the presence of metal chlorides. Reactions of organosilicon amides with phosgene gave corresponding carbenium salts, while organosilicon ureas yielded aminoiminocarbenium salts. Dialkylaminochlorocarbenium salts were reduced with hydrosilanes to give dialkylaminocarbenium salts and can be easily hydrolyzed to afford either amides or ureas. Pathways of the reaction with water and alcohols depend on the nature of reagent and the reaction conditions.
- Sheludyakov,Belyakova,Shevchenko,Chernyshev
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- Tunable and Practical Homogeneous Organic Reductants for Cross-Electrophile Coupling
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The syntheses of four new tunable homogeneous organic reductants based on a tetraaminoethylene scaffold are reported. The new reductants have enhanced air stability compared to current homogeneous reductants for metal-mediated reductive transformations, such as cross-electrophile coupling (XEC), and are solids at room temperature. In particular, the weakest reductant is indefinitely stable in air and has a reduction potential of -0.85 V versus ferrocene, which is significantly milder than conventional reductants used in XEC. All of the new reductants can facilitate C(sp2)-C(sp3) Ni-catalyzed XEC reactions and are compatible with complex substrates that are relevant to medicinal chemistry. The reductants span a range of nearly 0.5 V in reduction potential, which allows for control over the rate of electron transfer events in XEC. Specifically, we report a new strategy for controlled alkyl radical generation in Ni-catalyzed C(sp2)-C(sp3) XEC. The key to our approach is to tune the rate of alkyl radical generation from Katritzky salts, which liberate alkyl radicals upon single electron reduction, by varying the redox potentials of the reductant and Katritzky salt utilized in catalysis. Using our method, we perform XEC reactions between benzylic Katritzky salts and aryl halides. The method tolerates a variety of functional groups, some of which are particularly challenging for most XEC transformations. Overall, we expect that our new reductants will both replace conventional homogeneous reductants in current reductive transformations due to their stability and relatively facile synthesis and lead to the development of novel synthetic methods due to their tunability.
- Barth, Emily L.,Charboneau, David J.,Germe, Cameron C.,Hazari, Nilay,Huang, Haotian,Mercado, Brandon Q.,Uehling, Mycah R.,Zultanski, Susan L.
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p. 21024 - 21036
(2021/12/14)
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- Nickel-Catalyzed Enantioselective Cross-Coupling of N-Hydroxyphthalimide Esters with Vinyl Bromides
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An enantioselective Ni-catalyzed cross-coupling of N-hydroxyphthalimide esters with vinyl bromides is reported. The reaction proceeds under mild conditions and uses tetrakis(N,N-dimethylamino)ethylene as a terminal organic reductant. Good functional group tolerance is demonstrated, with over 20 examples of reactions that proceed with >90% ee.
- Suzuki, Naoyuki,Hofstra, Julie L.,Poremba, Kelsey E.,Reisman, Sarah E.
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supporting information
p. 2150 - 2153
(2017/04/27)
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- CYTOMEGALOVIRUS INHIBITOR COMPOUNDS
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Compounds of Formula (I) wherein n, A, R1, R2, R3 and R5 are defined herein, are useful for the treatment of cytomegalovirus disease and/or infection.
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Page/Page column 51; 52
(2013/10/22)
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- Orthoamides and iminium salts LXXIV [1]. Reactions of N,N,N',N'- Tetramethyl-chloroformamidiniumChloride with metals
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N,N,N',N'-Tetramethyl-formamidinium chloride (2a) reacts with elemental sodium in various solvents to give N,N,N',N',N'',N''-hexamethyl-guanidinium chloride (4a). The reaction of 2a with potassium affords N,N,N',N',N'',N'',N''', N'''-octamethyl-oxamidinium dichloride (3a). From the reaction of 2a with magnesium in different solvents in general result mixtures of the salts 4a, 3a and N,N,N',N'-tetramethyl-formamidinium chloride (10a). The composition of these mixtures depends on the solvent and the reaction temperature. Similar results are obtained, when a zinc'copper couple is used instead of magnesium. Very likely from 2a and magnesium or zinc, respectively, organometallic intermediates 11, 12 are formed which could be trapped by aromatic aldehydes and phenylisocyanate. The salt 2a can be reductively coupled by a low-valent titanium reagent to give the oxamidinium salt 3a.
- Kantlehner, Willi,Aichholz, Reiner,Karl, Martin
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p. 305 - 319
(2012/07/13)
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- New Syntheses of Methyleniminium Salts from Carbonyl Compounds and from α-Chloro Ethers; an Access to Vinylogous Viehe Salts
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Two methods for the synthesis of isolable methyleniminium salts and amidinium salts are presented.In the first case carbonyl compounds A are treated with a mixture of (dialkylamino)trimethylsilane (12) and chlorotrimethylsilane (13) or 12 and trimethylsilyl triflate (14) leading to the iminium chlorides F or iminium triflates G, respectively.With 12/13 the preparation of F is limited to non-enolizable aldehydes and dimethylformamide (10), while 12/14 enables the preparation of G, e.g. 23a-25a, 27a, also with ketones and with substituted amides.The second procedure is based on the treatment of α-chloro ethers L with 12.Both methods afford the Mannich reagent 16a in high yields.By reaction of the α-chloro ether 35 with 12 in diethyl ether the vinylogous Viehe salts 36a-c, e become available for the first time.The reaction pathways are discussed. - Key Words: Methyleniminium salts, preparation, mechanisms of formation / (Dialkylamino)trimethylsilanes / Ethers, α-chloro / Viehe salts, vinylogous
- Schroth, Werner,Jahn, Ullrich,Stroehl, Dieter
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p. 2013 - 2022
(2007/10/02)
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- A NOVEL AND SIMPLE METHOD FOR THE PREPARATION OF IMINIUM SALTS
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α-Chloroethers such as chloromethyl alkyl ethers of 1,3,3-trichloro-1-isobutoxyprop-2-ene react with trimethylsilyl-N,N-dialkylamines to give the Mannich-reagent and new 3,3-dichloroprop-2-en-1-ylidene-N,N-dialkyliminium chlorides (vinylogous Viehe-reagents), respectively.Extension of this method leads to the reagent system trimethylsilyl-N,N-dialkylamine/trimethylsilylchloride or -triflate, which allows the direct conversion of carbonyl compounds into iminium salts.
- Jahn, Ullrich,Schroth, Werner
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p. 5863 - 5866
(2007/10/02)
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- Reaction of Singlet Oxygen with Enamino Carbonyl Systems. A General Method for the Synthesis of α-Keto Derivatives of Lactones, Esters, Amides, Lactams, and Ketones
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A general method for the introduction of a ketone α to the carbonyl group of a ketone, lactone. ester, substituted amide, or lactam has been developed involving the formation and dye-sensitized photooxygenation of enamino carbonyl intermediates.
- Wasserman, Harry H.,Ives, Jeffrey L.
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p. 3573 - 3580
(2007/10/02)
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- Reactions with Phosphine Alkylenes, XLV. Reactions of Alkylidenetriphenylphosphoranes with Tetramethylformamidinium Chloride. Synthesis of triphenylphosphonium Chloride and (Formylalkylidene)triphenylphosphoranes
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Phosphonium ylides 1 react with tetramethylformamidinium chloride (2) to form enamine phosphonium chlorides 8 and the formic orthoamide 7.The salts 8 show temperature depending 1H NMR spectra with respect to the protons of the dimethylamino group (hindered rotation around the C - N(CH3)2 bond).Treatment of 8 with acids and subsequently with bases gives rise to the formation of the formyl ylides 19. 8a is deprotonated with sodium amide to give the phosphaallene ylide 20, which reacts with water to yield the phosphane oxide 21, and with methyl iodide stereospecifically to form 8b.
- Bestmann, Hans Juergen,Schmid, Guenter,Oechsner, Helmut,Ermann, Peter
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p. 1561 - 1571
(2007/10/02)
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- ZUR REAKTION VON P(III)AMIDEN MIT ORTHOAMEISENSAEUREESTERCHLORIDEN
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Both ester diamide, 2a, as well as diester amide, 2b, derivatives of phosphorous acid react with trichlorobenzodioxole, 1, to form the expected ester amide, 3, in small yields only.The main product is the dioxaphosphole, 4.Likewise, trisdimethylaminophosphine reacts with 1 with formation of the dioxaphosphole, 7.This unexpected reaction may be rationalized by assuming competition between N- and P-"diaryloxymethylenation" of the P(III)amide.A similar competition has been observed in the reaction of orthoformate with bis(dimethylamino)chlorophosphine.
- Costisella, Burkhard,Gross, Hans
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