- Activation and facile dealkylation of monooxides of 1,8-bis(alkylthio)naphthalene and 2,2′-bis(alkylthio)biphenyl with triflic anhydride via dithiadications
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Dithiadications bearing 1,8-bis(alkylthio)naphthalene 2A(a-e) and 2,2′-bis(alkylthio)biphenyl 2B(a-e) structure undergo either the facile deprotonation from the methyl group or dealkylation from the methylene groups by the triflate anion. Dications 2A(a) and 2B(a) having methyl groups were deprotonated readily to afford cyclic sulfonium salts 3A(a) and 3B(a). However, dithiadications 2A(b-e) and 2B(b-e) having ethyl, propyl, isopropyl and benzyl groups were readily dealkylated even at -45°C to give thiasulfonium salts 4A(b-e) and 4B(b-e) and alkyl triflates 5(a-e) in good yields. The intermediary formation of dithiadications 2A(a-e) and 2B(a-e) were confirmed by direct observation using NMR spectroscopy, D-labelled experiments and trapping experiments.
- Shima, Hidetaka,Kobayashi, Ryoji,Furukawa, Naomichi
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- Electrophilic Chemistry of Tetraphosphacubane: Novel Monophosphonium Ions of Ethylation, Benzylation, Acylation, and Adamantylation, Di- and Triphosphonium Ions of Acylation/Alkylation and Alkylation/Protonation, and Monoprotonation of Tetraoxo- and Tetrathioxotetraphosphacubane
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Ethyl triflate and benzyl triflate (via PhCH2Cl/AgOTf) react with the tetraphosphacubane 2a at room temperature to give the phosphonium salts 6 and 7.The P-adamantylated monocation 8 was obtained by the ambient temperature reaction of 2a with 1-Ad(1+)SbCl6(1-).P-Acylation of 2a with MeCO(1+)SbCl6(1-) gives 9, whereas the diphosphonium salt 11 is cleanly obtained by ambient temperature acylation of 6, adamantylation of 6 with 1-Ad(1+) is less selective, forming 13 in a mixture.Protonation of 6 with FSO3H*SbF5 (1:1) (magic acid)/SO2 gives a ca. 1:1 mixture of dication 14 and trication 15.The trication becomes more prominant with time or by an increase in temperature.Protonation of 5 similarly gives a mixture of 16 and 17, but the disappearance of 16 is very rapid.With HF/SbF5 (1:1)/SO2ClF only triphosphonium cation 17 is detected.Protonation of 6 with FSO3H*SbF5 (1:1)/SO2 leads to near exclusive formation of 14; only traces of 15 are detected.Tetraoxo- and tetrathioxotetraphosphacubanes 4a, 4b are only monoprotonated in Magic acid/SO2 (-> 18 and 19).PM3 calculations on protonation of tetramethyltetraphosphacubane 21 as model are also reported.
- Laali, Kenneth K.,Geissler, Bernhard,Regitz, Manfred,Houser, John J.
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- Trifluoromethyl Nonaflate: A Practical Trifluoromethoxylating Reagent and its Application to the Regio- and Stereoselective Synthesis of Trifluoromethoxylated Alkenes
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The trifluoromethoxy group has elicited much interest among drug and agrochemical discovery teams because of its unique properties. We developed trifluoromethyl nonafluorobutanesulfonate (nonaflate), TFNf, an easy-to-handle, bench-stable, reactive, and scalable trifluoromethoxylating reagent. TFNf is easily and safely prepared in a simple process in large scale and the nonaflyl part of TFNf can easily be recovered as nonaflyl fluoride after usage and recycled. The synthetic potency of TFNf was showcased with the underexplored synthesis of various trifluoromethoxylated alkenes, through a high regio- and stereoselective hydro(halo)trifluoromethoxylation of alkyne derivatives such as haloalkynes, alkynyl esters, and alkynyl sulfones. The synthetic merits of TFNf were further underscored with a high-yielding and smooth nucleophilic trifluoromethoxylation of alkyl triflates/bromides and primary/secondary alcohols.
- Hammond, Gerald B.,Kumon, Tatsuya,Lu, Zhichao,Umemoto, Teruo
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supporting information
p. 16171 - 16177
(2021/06/27)
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- Development of triazine-based benzylating reagents possessing T-butyl group on the triazine core: Thermally controllable reagents for the initiation of reaction
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Benzylating reagents, 4-(4,6-di-t-butyl-1,3,5-triazin-2-yl)-4-benzylmorpholinium triflate, and related derivatives have been developed. The reagents release benzyl triflate as a benzyl cation equivalent upon heating the solution to 40°C under neutral conditions. The O-benzylation of alcohols using a stoichiometric amount of these reagents afforded corresponding benzyl ethers in good to high yields. This was due to the presence of a bulky t-butyl group on the triazine ring of these reagents that prevents the consumption of benzyl triflate via a side reaction with a morpholinotriazine derivative.
- Karuo, Yukiko,Yamada, Kohei,Kunishima, Munetaka
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p. 303 - 308
(2018/03/09)
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- Synthesis of Benzonitrile from Dinitrogen
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The rhenium mediated synthesis of benzonitrile is reported with direct use of N2 as a nitrogen source. The reaction affords benzonitrile in about 30 % overall yield upon N2 splitting and benzylation of resulting terminal nitride. Sub
- Klopsch, Isabel,Schendzielorz, Florian,Volkmann, Christian,Würtele, Christian,Schneider, Sven
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p. 916 - 919
(2018/07/31)
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- Synthesis of Monothiomalonates – Versatile Thioester Enolate Equivalents for C–C Bond Formations
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Monothiomalonates (MTMs) are surrogates of thioester enolates that allow for stereoselective C–C bond formations under mild conditions and thereby afford access to synthetically versatile thioester derivatives. Here we present a straightforward synthetic route to MTMs that proceeds through nucleophilic ring-opening of Meldrum's acid derivatives followed by O-alkylation of the resulting malonic acid half thioesters with alkyl triflates or acetimidates as electrophiles. The method affords MTMs in overall yields of 34?–?92% and allows for variations of the oxo- and thioester moieties as well as the substituent at the C(α) position.
- Engl, Oliver D.,Saadi, Jakub,Cosimi, Elena,Wennemers, Helma
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- β-alkoxy-γ-amino aldehydes by internal redox ring cleavages of carbohydrate-derived enantiopure 1,2-oxazines and preparation of heterocycles with aminopolyol side chain
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N-Methylation of syn- or anti-configured 3,6-dihydro-2H-1,2-oxazines and subsequent treatment with triethylamine smoothly provided enantiopure α,β-unsaturated β-alkoxy-γ-amino aldehydes bearing different protected diol, triol, or tetrol side chains in goo
- Al-Harrasi, Ahmed,Bouche, Lea,Zimmer, Reinhold,Reissig, Hans-Ulrich
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experimental part
p. 109 - 118
(2011/03/19)
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- Novel benzothienyl or indole derivatives, preparation and use thereof as inhibitors of prenyl transferase proteins
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The invention concerns compounds of general formula (1), wherein, in particular; W represents H, SO2R5. CO(CH2)nR5, (CH2)nR6, CS(CH2)nR5; X represents S or NH; Y represents (CH2)p, CO, (CH2)pCO, CH═CH—CO; Z represents a hetcrocycle, imidazole, benzimidazole, isoxazole, tetrazole, oxadiazole, thiadazole, pyridine, quinazoline, quinoxaline, quinoline, thiophene; R1 represents COOR6, CONR6R7, CO—NH—CH(R6)—COOR7, CH2NR6R7, CH2OR6, (CH2)pR6, CH═CHR6; R2 represents in particular hydrogen, C1-C10 alkyl, a substituted or unsubstituted phenyl; R5 and R6 represents hydrogen, C1—C6 alkyl; R5 represents a substituted or unsubstituted phenyl or naphthyl; R6 and R7, identical or different, represent hydrogen, C1—C15 alkyl, a hetcrocycle. an aryl; n represents 0 to 10; p represents 1 to 6.
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- Regioselective synthesis of substituted o-alkoxyphenol derivatives through thermal benzannulation of Fischer (alkenylcyclobutenyl)carbene complexes
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A convenient, regioselective, and general synthetic method for producing highly substituted o-phenol-containing polycycles from Fischer (alkenylcyclobutenyl)carbene complexes has been described. The starting complexes have been synthesized by means of the [2 + 2] cycloaddition reaction of (alkenylethynyl)carbene complexes and a range of enol ethers, and in most cases, they have proven to be stable at room temperature and therefore isolable. The key step of the synthesis consists of the thermal benzannulation reaction of these novel pentacarbonyl dienyl Fischer complexes, which is an unprecedented transformation for these kinds of complexes. The unexpected behavior of (alkenylcyclobutenyl)carbene complexes has been rationalized in terms of their geometries.
- Barluenga, Jose,Aznar, Fernando,Palomero, M. Angel
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p. 537 - 544
(2007/10/03)
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- Synthesis and evaluation of sulfonium analogues of isofucofagomine as glycosidase inhibitors
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A series of L-fucopyranose analogues having a sulfur substituent at the anomeric position were synthesised. A sulfide, a methylsulfonium ion, a sulfoxide and a sulfone analogue were made. The synthesised compounds were tested for inhibition of two α-fucos
- Ulgar, Victor,Fernandez-Bolanos, Jose G.,Bols, Mikael
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p. 1242 - 1246
(2007/10/03)
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- Transannular and intermolecular interactions between chalcogen atoms: Syntheses and properties of dichalcogena dications and trichalcogena hypervalent dications
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Intramolecular (transannular) and intermolecular through-space interactions between chalcogen atoms have been described. This account includes the following three topics. (1) Various types of bis-chalcogenides and their mono-oxides, which have the two chalcogen atoms in close proximity in a molecule, give the dichalcogena dications upon the oxidation with two equivalents of NOBF4 or treatment with one equivalent of triflic anhydride (Tf2O). The stability of the dichalcogena dications increases in the order S N1 type reaction to form chalcogenachalcogenonium salts and alkyl cations. (2) The reaction of 2,6-bis[(phenylthio- or phenylseleno)methyl]phenyl phenyl telluride or the corresponding Te-oxide with NOBF4 or Tf2O affords the positively-charged hypervalent species, dicationic telluranes. Dicationic telluranes can be prepared by the remote oxidation through π-conjugation. The stable sulfenium cation can be isolated by taking advantage of 2,6-bis[(dimethylamino)methyl]phenyl ligand. (3) The remote oxygen migration and Pummerer reactions of p-bis(methylthio)-aromatic mono-oxides are discussed in light of an intermolecular through-space interaction between sulfur atoms, and a cyclic bis(dithia dication) dimer is proposed as an intermediate.
- Furukawa, Naomichi,Kobayashi, Kenji,Sato, Soichi
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p. 116 - 126
(2007/10/03)
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- Discovery and structure-activity relationships of imidazole-containing tetrahydrobenzodiazepine inhibitors of farnesyltransferase
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2,3,4,5-Tetrahydro-1-(imidazol-4-ylalkyl)-1,4-benzodiazepines were found to be potent inhibitors of farnesyltransferase (FT). A hydrophobic substituent at the 4-position of the benzodiazepine, linked via a hydrogen bond acceptor, was important to enzyme i
- Ding, Charles Z.,Batorsky, Roberta,Bhide, Rajeev,Chao, Hannguang J.,Cho, Young,Chong, Saeho,Gullo-Brown, Johnni,Guo, Peng,Kim, Soong Hoon,Lee, Frank,Leftheris, Katerina,Miller, Arthur,Mitt, Toomas,Patel, Manorama,Penhallow, Becky A.,Ricca, Carol,Rose, William C.,Schmidt, Robert,Slusarchyk, William A.,Vite, Gregory,Yan, Ning,Manne, Veeraswamy,Hunt, John T.
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p. 5241 - 5253
(2007/10/03)
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- Stereocontrol of stereogenic centres para on a benzene ring using the SE2″ reaction of a pentadienylsilane
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The pentadienylsilane 9 and the dimethyl acetal 2 of isobutyraldehyde react with high (80:20) anti stereospecificity to give largely the diene 10a, which was converted into the Para-disubstituted benzene 11a, having 1,6-related stereogenic centres.
- Fleming, Ian,Leslie, Colin P.
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p. 1197 - 1203
(2007/10/03)
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- Activation and facile dealkylation of monooxides of 2,2′-bis(alkylthio)biphenyl with triflic anhydride via dithiadications: A new method for preparation of thiasulfonium salts
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Monooxides of 2,2′-bis(alkylthio)biphenyl undergo facile monodealkylation on treatment with triflic anhydride to afford the corresponding thiasulfonium salts except bis(methylthio) derivative. The reaction proceeds via an initial formation of the corresponding dithiadications.
- Shima, Hidetaka,Kobayashi, Ryoji,Nabeshima, Tatsuya,Furukawa, Naomichi
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p. 667 - 670
(2007/10/02)
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- Hydrocarbon and Phosphate Triester Formation during Homolytic Hydrolysis of Organophosphonium Ions: An Alternate Model for Organophosphonate Biodegradation
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Treatment of organotrineopentoxyphosphonium trifluoromethanesulfonates with base and organic peroxides results in carbon to phosphorus (C-P) bond cleavage. The products of the homolytic hydrolysis are hydrocarbons and trineopentyl phosphate. Reaction of the organophosphonium ions with only base leads to oxygen to phosphorus (O-P) bond cleavage with a complete absence of C-P bond cleavage. The likely intermediacy of a pentacovalent phosphonyl radical during the homolytic hydrolysis provides the basis for an alternate mechanistic formulation for the C-P bond cleavage observed during organophosphonate biodegradation. This formulation is unique in its prediction of inorganic phosphate as the immediate phosphorus-containing product of microbe-mediated C-P bond cleavage.
- Avila,Bishop,Frost
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p. 2242 - 2246
(2007/10/02)
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- An Efficient Stereocontrolled Route to Both Enantiomers of Platelet Activating Factor and Analogues with Long-Chain Esters at C2: Saturated and Unsaturated Ether Glycerolipids by Opening of Glycidyl Arenesulfonates
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Both enantiomers of various ether/ester glycerophospholines (R)- and (S)-1, including platelet activating factor (PAF, 2), have been synthesized from arenesulfonate derivatives of glycidol ((R)- and (S)-3) that are readily available in high enantiomeric p
- Guivisdalsky, Pedro N.,Bittman, Robert
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p. 4643 - 4648
(2007/10/02)
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- Chirospecific Synthesis of β-Hydroxy α-Amino Acids
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A variety of β-hydroxy α-amino acids have been synthesized with complete enantiomeric purity from L-serine.These include β-hydroxyglutamic acid, β-hydroxypipecolic acid, β-hydroxylysine, β-hydroxyproline, and β-hydroxymethionine.The syntheses proceed by t
- Roemmele, Renee C.,Rapoport, Henry
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p. 1866 - 1875
(2007/10/02)
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