- Synthesis of Organic (Trimethylsilyl)chalcogenolate Salts Cat[TMS-E] (E = S, Se, Te): the Methylcarbonate Anion as a Desilylating Agent
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A high-yield synthesis of the class of (trimethylsilyl)chalcogenolate organic salts [Cat][TMS-E] (E = S, Se, Te; Cat = BMPyr, DMPyr, NMe4, nBu3MeP) is presented. The title compounds have been prepared by the strictly aprotic reaction between the respective bis(trimethylsilyl)chalcogenide (TMS2E) and methylcarbonate ionic liquids (ILs). This constitutes a novel reaction behavior of methylcarbonate ILs, acting as a nucleophilic desilylating agent and a Lewis base instead of as a Bronsted base. Thus prepared silylchalcogenolate salts represent an activated form of the multifunctional TMS2E reactant series. Pyrrolidinium TMS-S salts have proven to be excellent precursors for the synthesis of pyrrolidinium hexasulfides. The scope of the desilylation reaction can be extended to other silyl-bearing synthons such as (trimethylsilyl)azide and (trimethylsilyl)cyanide.
- Finger, Lars H.,Scheibe, Benjamin,Sundermeyer, J?rg
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supporting information
p. 9568 - 9575
(2015/10/12)
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- Orthoamides, XL. - Preparation of 1,1,2,3,3-Pentasubstituted and 1,1,2,2,3,3-Hexasubstituted Guanidinium Salts and 1,1,2,3,3-Pentaalkylguanidines
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N,N,N',N'-(Tetramethyl)thiourea (1) reacts with N,N-dimethylcarbamoyl chloride (2) to give the guanidinium salt 3a.The carbenium salt 4, obtained from 1 and dimethyl sulfate, affords on treatment with dimethylamine the guanidinium salt 3b.Reaction of phosgene with N,N,N',N'-tetraalkylureas yields the chloroformamidinium chlorides 5 which are transformed by mixtures of primary or secondary amines and tertiary amines into mixtures of guanidinium salts and ammonium salts.From these mixtures, by means of sodium hydroxide, have been isolated the guanidinium salts 3a, 6, and 11, respectively.Some of the salts 3a and 6 are converted into the corresponding tetraphenylborates 7.The fluoroborates 8a and 8b are obtained from guanidinium chlorides 3a and 6h, respectively.By anion exchange in 8a, b the salts 9, 10 have been prepared.Alkylation of the guanidines 12 affords the guanidinium salts 13.
- Kantlehner, Willi,Haug, Erwin,Mergen, Walter W.,Speh, Peter,Maier, Thomas,et al.
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p. 108 - 126
(2007/10/02)
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- Orthoamides, XXXV. - Preparation of O,N-Functional Trisubstituted Acetonitriles
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Trichloroacetonitrile (7) reacts with molar amounts of alcoholates in alcohols to give mixtures of orthocarbonates 10 and trichloroacetimidates 9.The action of 7 on 3 moles of sodium ethoxide in heptane affords triethoxyacetonitrile 3b among other products, such as 9b, 10b and the imidate 12.The nitrile 3a can be obtained from 7 and sodium methoxide in ether in moderate yields. - The orthocarbonic acid derivatives 10b, 20a and 21a are transformed by acyl cyanides into the nitriles 3b, 4a, and 5a, respectively.N,N,N',N',N'',N''-hexamethylguanidinium cyanide (23a) is f ormed in the reaction of 22 with acetyl cyanide. - The salts 30a-32a react with alkali cyanides to form the nitriles 3b, 4a, and 5a, respectively.The nitrile 2a transfers cyanide ions to the carbenium ions 30a and 31a to yield the nitriles 3b and 4a, respectively.
- Kantlehner, Willi,Maier, Thomas,Kapassakalidis, Joannis J.
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