Über Chalkogenolate. LXII. Untersuchungen über Halbester der Kohlensäure 2. Darstellung und Eigenschaften der Monomethylkohlensäure

Behrendt, Werner; Gattow, G.

doi:10.1002/zaac.19733980214

Cited by 22 publications

(12 citation statements)

References 15 publications

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“…Formation of the allylic sulfides with pyrimidinethiol (p K a 7.1339a), 4‐chlorothiophenol (p K a 7.0639b) and 2‐pyridinethiol (p K a 9.8139c) but not with tert ‐butylthiol (p K a 11.0539d) may be related to their different acidity. The thiols are expected to react with the leaving group MeOCO 2 − (p K a 5.6139e) under deprotonation to give the corresponding thiolates, which ought to be the more reactive nucleophiles [Eq. (1)].…”

Section: Resultsmentioning

confidence: 99%

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Highly Selective Palladium Catalyzed Kinetic Resolution and Enantioselective Substitution of Racemic Allylic Carbonates with Sulfur Nucleophiles: Asymmetric Synthesis of Allylic Sulfides, Allylic Sulfones, and Allylic Alcohols

Gais

Jagusch

Spalthoff

et al. 2003

Chemistry A European J

128

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We describe the highly selective palladium catalyzed kinetic resolutions of the racemic cyclic allylic carbonates rac-1 a-c and racemic acyclic allylic carbonates rac-3 aa and rac-3 ba through reaction with tert-butylsulfinate, tolylsulfinate, phenylsulfinate anions and 2-pyrimidinethiol by using N,N'-(1R,2R)-1,2-cyclohexanediylbis[2-(diphenylphosphino)-benzamide] (BPA) as ligand. Selectivities are expressed in yields and ee values of recovered substrate and product and in selectivity factors S. The reaction of the cyclohexenyl carbonate 1 a (>/=99 % ee) with 2-pyrimidinethiol in the presence of BPA was shown to exhibit, under the conditions used, an overall pseudo-zero order kinetics in regard to the allylic substrate. Also described are the highly selective palladium catalyzed asymmetric syntheses of the cyclic and acyclic allylic tert-butylsulfones 2 aa, 2 b, 2 c, 2 d and 4 a-c, respectively, and of the cyclic and acyclic allylic 2-pyrimidyl-, 2-pyridyl-, and 4-chlorophenylsulfides 5 aa, 5 b, 5 ab, 6 aa-ac, 6 ba and 6 bb, respectively, from the corresponding racemic carbonates and sulfinate anions and thiols, respectively, in the presence of BPA. Synthesis of the E-configured allylic sulfides 6 aa, 6 ab, 6 ac and 6 bb was accompanied by the formation of minor amounts of the corresponding Z isomers. The analogous synthesis of allylic tert-butylsulfides from allylic carbonates and tert-butylthiol by using BPA could not be achieved. Reaction of the cyclopentenyl esters rac-1 da and rac-1 db with 2-pyrimidinethiol gave the allylic sulfide 5 c having only a low ee value. Similar results were obtained in the case of the reaction of the cyclohexenyl carbonate rac-1 a and of the acyclic carbonates rac-3 aa and rac-3 ba with 2-pyridinethiol and lead to the formation of the sulfides 5 ab, 6 ab, and 6 bb, respectively. The low ee values may be ascribed to the operating of a "memory effect", that is, both enantiomers of the substrate give the substitution product with different enantioselectivities. However, in the reaction of the racemic carbonate rac-1 a as well as of the highly enriched enantiomers 1 a (>/=99 % ee) and ent-1 a (>/=99 % ee) with 2-pyrimidinethiol the ee values of the substrates and the substitution product remained constant until complete conversion. Similar results were obtained in the reaction of the cyclic carbonates rac-1 a, ent-1 a (>/=99 % ee) and ent-1 c (>/=99 % ee) with lithium tert-butylsulfinate. Thus, in the case of rac-1 a and 2-pyrimidinthiol and tert-butylsulfinate anion as nucleophiles the enantioselectivity of the substitution step is, under the conditions used, independent of the chirality of the substrate; this shows that no "memory effect" is operating in this case. Hydrolysis of the carbonates ent-1 a-c, ent-3 aa and ent-3 ba, which were obtained through kinetic resolution, afforded the enantiomerically highly enriched cyclic allylic alcohols 9 a-c (>/=99 % ee) and acyclic allylic alcohols 10 a (>/=99 % ee) and 10 b (99 % ee), respectively.

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Section: Resultsmentioning

confidence: 99%

“…Furthermore the equilibrium between the leaving group and the thiol could be shifted to the side of the thiolate because of a decomposition of methyl carbonate with formation of carbon dioxide and methanol [Eq. (2)] 39e, MeOCO 2 − +RSH ⇌ MeOCO 2 H+RS − MeOCO 2 H →CO 2 + MeOH …”

Section: Resultsmentioning

confidence: 99%

Highly Selective Palladium Catalyzed Kinetic Resolution and Enantioselective Substitution of Racemic Allylic Carbonates with Sulfur Nucleophiles: Asymmetric Synthesis of Allylic Sulfides, Allylic Sulfones, and Allylic Alcohols

Gais

Jagusch

Spalthoff

et al. 2003

Chemistry A European J

128

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“…Furthermore we want to emphasize that there is in fact one single report of a successful isolation of a pure hemiester of carbonic acid, namely CAME (HO 2 COCH 3 ) by Behrendt et al in the 1970s. 11 , 12 This was achieved via synthesis of alkali metal monoalkyl carbonates M[O 2 COR], 13 following the protocol of Dumas and Peligot established in 1840. 14 The protonated form could then be formed by interaction between a suspension of the salt Na[O 2 COCH 3 ] in dimethyl ether and a solution of HCl in dimethyl ether under cryoconditions, namely at 223 K. 11 , 12 After distilling off dimethyl ether at 193 K, CAME could be isolated as a pure, colourless solid of melting point 237 K. Its IR spectrum and acid dissociation constant p K a were also determined by Behrendt et al 11 , 12 The IR spectrum led them to conclude that CAME exists as a monomer.…”

Section: Introductionmentioning

confidence: 99%

Carbonic acid monoethyl ester as a pure solid and its conformational isomerism in the gas-phase

et al. 2017

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“…This observation combined with the observation of Bridges et al [11] that a bicarbonate quaternary in the presence of methanol forms methyl carbonate suggests that the conversion is actually an equilibrium. Since the K b of the methyl carbonate ion in water is about ten times larger than acetate [19], it is likely that methyl carbonate is a strong enough base to catalyze its de-esterification producing bicarbonate and methanol.…”

Section: Physical Characterization Of Methyl Carbonate Quaternariesmentioning

confidence: 99%

Investigation of the Stability of Quaternary Ammonium Methyl Carbonates

Weisshaar

Earl

Amolins

et al. 2011

J Surfact & Detergents

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Quaternary ammonium compounds are used commercially for a variety of applications and some are of interest as ionic liquids. For many years dimethyl carbonate has been touted as a green reagent, including its use for methylation (quaternization) of tertiary amines. In addition, substitution of the methyl carbonate by other anions can be efficiently and cleanly accomplished by reaction with the corresponding acid. How stable are these methyl carbonate quaternary compounds? High field 13 C NMR shows that in the presence of water, the methyl carbonate is converted to bicarbonate. Headspace GCMS indicates that the alkylammonium methyl carbonate salts are stable below 170-180°C while the bicarbonate salts are stable to only about 140°C. Thermal decomposition occurs by decarboxylation and by dealkylation.

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Über Chalkogenolate. LXII. Untersuchungen über Halbester der Kohlensäure 2. Darstellung und Eigenschaften der Monomethylkohlensäure

Cited by 22 publications

References 15 publications

Highly Selective Palladium Catalyzed Kinetic Resolution and Enantioselective Substitution of Racemic Allylic Carbonates with Sulfur Nucleophiles: Asymmetric Synthesis of Allylic Sulfides, Allylic Sulfones, and Allylic Alcohols

Highly Selective Palladium Catalyzed Kinetic Resolution and Enantioselective Substitution of Racemic Allylic Carbonates with Sulfur Nucleophiles: Asymmetric Synthesis of Allylic Sulfides, Allylic Sulfones, and Allylic Alcohols

Carbonic acid monoethyl ester as a pure solid and its conformational isomerism in the gas-phase

Investigation of the Stability of Quaternary Ammonium Methyl Carbonates

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