- Lewis acid mediated, mild C-H aminoalkylation of azolesviathree component coupling
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This manuscript reports the development of a mild, highly functional group tolerant and metal-free C-H aminoalkylation of azolesviaa three-component coupling approach. This method enables the C-H functionalization of diverse azole substrates, such as oxazoles, benzoxazoles, thiazoles, benzothiazoles, imidazoles, and benzimidazoles. DFT calculations identify a key deprotonation equilibrium in the mechanism of the reaction. Using DFT as a predictive tool, the C-H aminoalkylation of initially unreactive substrates (imidazoles/benzimidazoles) can be enabled through anin situprotecting/activating group strategy. The DFT-supported mechanistic pathway proposes key interactions between the azole substrate and the Lewis acid/base pair TBSOTf/EtNiPr2that lead to azole activation by deprotonation, followed by C-C bond formation between a carbene intermediate and an iminium electrophile. Two diverse approaches are demonstrated to explore the amine substrate scope: (i) a DFT-guided predictive analysis of amine components that relates reactivity to distortion of the iminium intermediates in the computed transition state structures; and (ii) a parallel medicinal chemistry workflow enabling synthesis and isolation of several diversified products at the same time. Overall, the presented work enables a metal-free approach to azole C-H functionalizationviaLewis acid mediated azole C-H deprotonation, demonstrating the potential of a readily available, Si-based Lewis acid to mediate new C-C bond formations.
- Emmert, Marion H.,He, Cyndi Qixin,Shah, Akshay A.,Felten, Stephanie
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p. 3890 - 3897
(2021/04/02)
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- An Alumino-Mannich Reaction of Organoaluminum Reagents, Silylated Amines, and Aldehydes
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A multi-component coupling using organoaluminum reagents, silylated amines, and aldehydes results in the formation of tertiary amines. Both alkenyl- and alkylaluminum reagents undergo reaction with iminium ion substrates for which the corresponding Petasis borono-Mannich reactions are unsuccessful.
- Tarasewicz, Anika,Ensan, Deeba,Batey, Robert A.
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supporting information
p. 6071 - 6074
(2018/04/27)
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- Insertion of phenyl isocyanate into monoand diaminosilanes
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The aminosilanes MenSi(NRR')4-n (n = 2,3) with NRR' = ethylamino (NHEt), n-propylamino (NHnPr), sec-butylamino (NHsBu), n-octylamino (NHnOct), n-dodecylamino (NHnDodec), allylamino (NHAll), tert-butylamino (NHtBu), diethylamino (NEt2), and anilino (NHPh) were synthesized and their reactions with phenyl isocyanate were studied. In all cases of these silanes Me3SiNRR' and Me2Si(NRR')2 formal insertion of the -NCO group into their Si-N bonds was observed, i.e. formation of products with Si-N (rather than Si-O) bonds was found. In some cases, the products could be crystallized and their molecular structures have been elucidated with single-crystal X-ray diffraction analyses.
- Kraushaar, Konstantin,Herbig, Marcus,Schmidt, Dana,Wagler, J?rg,B?hme, Uwe,Kroke, Edwin
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p. 909 - 921
(2018/01/19)
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- Nucleophilic bromodifluoromethylation of iminium ions
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A method for bromodifluoromethylation of iminium ions using Me3SiCF2Br is described. The reaction involves room temperature activation of the silicon reagent by HMPA to generate difluorocarbene, which upon interacting with excess of bromide ion provides bromodifluoromethyl carbanionic species. The iminium electrophiles are generated in situ from aldehydes, secondary amines, proton sponge, and silyl triflate. The reaction can be extended for introduction of chlorodifluoromethyl and iododifluoromethyl groups.
- Tsymbal, Artem V.,Kosobokov, Mikhail D.,Levin, Vitalij V.,Struchkova, Marina I.,Dilman, Alexander D.
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p. 7831 - 7835
(2015/03/18)
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- Three-component coupling using arynes and aminosilanes for ortho-selective double functionalization of aromatic skeletons
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(Chemical Equation Presented) Arynes were found to couple with aminosilanes and carbonyl compounds in the presence of benzoic acid to provide 2-aminobenzhydrols. Sulfonylimines could also be applied to the reaction, enabling amino and aminomethyl moieties to be incorporated into contiguous positions of aromatic skeletons. Only a small amount of the three-component coupling product was obtained in the absence of benzoic acid, which confirms its vital role in the present reaction.
- Morishita, Takami,Fukushima, Hiroyuki,Yoshida, Hiroto,Ohshita, Joji,Kunai, Atsutaka
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p. 5452 - 5457
(2008/12/20)
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- Three-component coupling of arynes, aminosilanes, and aldehydes
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A three-component coupling of arynes, aminosilanes, and aldehydes enables diverse amino and hydroxymethyl groups to be incorporated directly into 1,2-positions of aromatic rings.
- Yoshida, Hiroto,Morishita, Takami,Fukushima, Hiroyuki,Ohshita, Joji,Kunai, Atsutaka
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p. 3367 - 3370
(2008/02/11)
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- Kinetics and mechanisms of silylation reactions: I. Catalytic alcoholysis and phenolysis of trimethylsilanes
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Solvolysis of trimethyl(4-nitrophenoxy)silane and diethylamino(trimethyl)silane in 2-propanol, catalyzed by 4-nitrophenol and diethylamine, follows a scheme including 16 concurrent and consecutive reactions with participation of trimethylsilyl cation. Quantitative analysis of different reaction pathways shows that the main factor determining the predominant transformation pathways is specific solvation.
- Popov,Anikeev
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p. 1770 - 1776
(2007/10/03)
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- Novel method for preparing bis(trimethylsilyl) amines via treatment with trimethylsilylamines and methyl iodide
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A convenient method for the synthesis of N,N-bis(trimethylsilyl)alkylamines has been reported. N-(Trimethylsilyl)diethylamine incorporated with a stoichiometric amount of methyl iodide was effective to convert primary amines, especially aromatic amines, and their monotrimethylsilyl derivatives into the corresponding N,N-bis(trimethylsilyl)amine derivatives in high yields. In the case of N-trimethylsilyl derivatives of aliphatic primary amines, a half-amount of silylamines served as a silylation agent against another half-amount of silylamines in the presence of 0.5 equivalent of methyl iodide to give N,N-bis(trimethylsilyl)alkylamines in good yield. Allyl iodide, allyl bromide and benzyl bromide were also effective to promote the silylation activity of silylamines.
- Hamada, Yoshitaka,Yamamoto, Yasushi,Shimizu, Hideaki
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- Simple acid-base hydrolytic chemistry approach to new materials for second-order non-linear optics
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Acid-base hydrolysis of aminqsilanes with NLO-active chromophores containing terminal acidic protons provides a facile synthetic route to robust dimeric, polymeric and molecularly self-assembled thin-film materials for second-order non-linear optics.
- Jiang, Hongwei,Kakkar, Ashok K.,Lebuis, Anne-Marie,Zhou, Haitian,Wong, George K.
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p. 1075 - 1077
(2007/10/03)
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- A Convenient Molecular Self-assembly Route to Thin Films containing Terminal Donor Ligands and Anchored Organotransition-metal Complexes for Heterogenized Homogeneous Catalysis
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Simple acid-base hydrolytic chemistry on the surfaces of glass, quartz or silicon provides an easy access to thin films containing terminal amine and phosphine donor ligands which covalently bind a variety of organometallic complexes, and such oriented ultrathin films supporting a densely packed nickel(0) organometallic complex on glass, catalyse oligomerization of phenylacetylene.
- Petrucci, Maria G. L.,Kakkar, Ashok K.
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p. 1577 - 1578
(2007/10/02)
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- A Novel Route to Efficient Inorganic Oxide Surface Modifications: Molecularly Self-assembled Linear and Conjugated Alkynyl Thin Film Materials
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Treatment of surface hydroxy groups on glass, quartz and single crystal silicon with commercially available group 14 chlorides, ECl4 (E = Si, Sn), and then NEt2H yields surface-anchored NEt2 moieties, which react with several organic molecules containing terminal acidic protons, including rigid-rod alkynes, via acid-base hydrolysis, leading to molecularly self-assembled chromophoric monolayers.
- Yam, Chi Ming,Kakkar, Ashok K.
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p. 907 - 910
(2007/10/02)
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- DIALKYL(TRIMETHYLSILYL)TETRATHIOPHOSPHATES IN SYNTHESIS OF SUBSTITUTED TETRATHIOPHOSPHATES
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Reactions of S,S'-dialkyl-S''-trimethylsilyl tetrathiophosphates with aldehydes, acetals, ortho ethers, aminals, thioacetals, bis(thiocyanato)methane, disulfides and alkyl halides resulted in the products of tetrathiophosphate structure.Key words: S,S'-Dialkyl-S''-trimethylsilyl tetrathiophosphates; organic substances; substituted tetrathiophosphates.
- Nizamov, Il'Yas S.,Kuznetzov, Vladislav A.,Batyeva, Elvira S.
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p. 249 - 258
(2007/10/02)
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- DIALKYL TRIMETHYLSILYL TETRATHIOPHOSPHATES. SYNTHESIS AND TRANSFORMATIONS
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We have developed an efficient method for synthesizing dialkyl trimethylsilyl tetrathiophosphates, which react with aldehydes, acetals, ortho esters, thioacetals, bis(thiocyanato)methane, diethyl disulfide, and alkyl halides to give a number of new tetrathiophosphate derivatives.
- Nizamov, I.S.,Kuznetsov, V.A.,Batyeva, E.S.,Al'fonsov, V.A.
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p. 1196 - 1198
(2007/10/02)
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- Trialkylsilylating agent and process for preparing N,N-disubstituted aminotrialkylsilane using the same
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A silylating agent comprising an N-(trialkylsilyl)benzanilide having the following general formula: STR1 wherein R1 is a lower alkyl group. This agent is reacted with a secondary amine to produce an N,N-dialkylaminotrialkylsilane. This process is free of formation of amine hydrochlorides as by-products. Therefore, the problem associated with disposal of such amine hydrochlorides and the problem of limitations on the use of the silane compound product due to mixing of such amine hydrochlorides can be obviated effectively.
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- REACTION OF DIALKYL TRIMETHYLSILYL DITHIOPHOSPHITES WITH SULFENAMIDES
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Dialkyl trimethylsilyl dithiophosphites react with sulfenamides either through involvement of the trimethylsilyl group and the formation of trialkyl trithiophosphates or by isomerization of the starting silylphosphites to give S-alky O-trimethylsilyl alkyldithiophosphonates.The direction of the reaction depends on the nature of the substituents at the sulfur atoms of the silylphosphite and sulfenamide.
- Al'fonsov, V. A.,Trusenev, A. G.,Batyeva, E. S.,Pudovik, A. N.
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p. 1955 - 1956
(2007/10/02)
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- Process for preparing polyisocyanato/polyisocyanurates by catalytic cyclotrimerization of polyisocyanates
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Polyisocyanurate/polyisocyanates of enhanced stability are prepared by partial catalytic cyclotrimerization of a polyisocyanate in the presence of a catalytically effective amount of an aminosilyl catalyst and wherein the cyclotrimerization reaction is terminated when a predetermined desired amount of isocyanurate groups has been attained, by adding to the reaction mixture, after the cooling thereof to a temperature of below 50° C., a reaction terminating amount of an organic catalyst deactivating compound comprising at least one free hydroxyl moiety, or the reaction product of such hydroxylated organic catalyst deactivating compound with an isocyanate.
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- Barriers to Internal Rotation in 1,3,5-Trineopentylbenzenes.10. 13C and 19F NMR Band Shape Studies and Force Field Calculations.
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1,3,5-Trineopentylbenzenes (TNB) with one or two benzylic substituents in each neopentyl group were synthesized.The substituents were F, Cl, Br, I, OCH3, OCOCH3, OSi(CH3)3 and CH3 and, in cases of disubstitution, F, Cl, Br, CH3 and Cl, CH3 and Br and -SCH2CH2S-.Barriers to internal Csp3-Csp2 (aryl) and Csp3-Csp3 rotation were estimated by 13C and 19F NMR band shape methods.Estimated barriers in the TNB series were found to be very close to those found for the corresponding mononeopentylbenzenes.For some of the compounds studied, molecular mechanics (MM) calculations were performed with the Allinger MMP1 program.Differ ences between calculated and experimental estimated barriers were found, and possible sources of these discrepancies in terms of parameters used in the MMP1 program are discussed.
- Andersson, Sven,Drakenberg, Torbjoern
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p. 602 - 615
(2007/10/02)
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- TRIMETHYLSILYL TRIFLATE IN ORGANIC SYNTHESIS
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Trimethylsilyl triflate is a powerful silylating agent for organic compounds and acts as a catalyst which accelerates a variety of nucleophilic reactions in aprotic media.The reactions proceed via one-center, electrophilic coordination of the silyl group to hetero functional groups and exhibit unique selectivities.
- Noyori, R.,Murata, S.,Suzuki, M.
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p. 3899 - 3910
(2007/10/02)
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- SILYLATION WITH A PERFLUORINATED RESINSULFONIC ACID TRIMETHYLSILYL ESTER
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A new polymer-supported silylating agent, Nafion-TMS, is introduced.
- Murata, S.,Noyori, R.
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p. 767 - 768
(2007/10/02)
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- 19-Hydroxy-PGI2 compounds
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Prostacyclin and prostacyclin-type derivatives having a 19-hydroxy feature are disclosed, including processes for preparing them and the appropriate intermediates. The compounds are useful for pharmacological purposes such as inhibition of blood platelate aggregation.
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- 2-Decarboxy-2-hydroxymethyl-19-hydroxy-PG1 analogs
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Prostaglandin derivatives having a 19,20-didehydro, a 19-hydroxy, or a 19-keto feature are disclosed, including processes for preparing them and the appropriate intermediates. A typical 19-hydroxy compound of this invention is 19-hydroxy-19-methyl-PGF2α, methyl ester, represented by the formula STR1
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- Bicyclic lactones
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Process for preparing bicyclic lactone acrylic aldehydes and ketones of the formula STR1 wherein "n" is one or 2, wherein R1, is hydrogen, methyl, or ethyl, and wherein R4 is hydrogen or a blocking group; and those aldehydes, ketones, and intermediates prepared therein. The aldehydes and ketones are useful intermediates in preparing prostaglandins and analogs having pharmacological utility.
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