Hydrophobic <i>N,N-</i>Diarylammonium Pyrosulfates as Dehydrative Condensation Catalysts under Aqueous Conditions

Sakakura, Akira; Koshikari, Yoshiki; Akakura, Matsujiro; Ishihara, Kazuaki

doi:10.1021/ol2027366

Cited by 32 publications

(16 citation statements)

References 30 publications

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“…Based on the success of DPAT, a series of analogous ammonium salts was similarly prepared and screened for dehydrative glycosylation. In general, catalysts prepared from either dialkylamines (entries 6-7) or less acidic Brønsted acids, such as methanesulfonic acid (pKa (H 2 O) = -1.9, entry 8) [22], benzenesulfonic acid (pKa (H 2 O) = -2.8, entry 9) [17][18][19][20][21], or p-toluenesulfonic acid (pKa (H 2 O) = -2.1, entry 10) [23] were inactive. Only catalysts generated from Brønsted acids having acidity similar to that of triflic acid (pKa (H 2 O) = -14.7), such as perchloric acid (pKa (H 2 O) = -15.2) [24], gave comparable yields (entry 11).…”

Section: Resultsmentioning

confidence: 99%

“…The shift from metal to metal-free catalysis is the current trend for greener and more sustainable chemistry. Arylammonium triflates and bulky diarylammonium arenesulfonates were introduced by Tanabe [15,16] and Ishihara [17][18][19][20][21], respectively, to be effective catalysts for direct dehydrative esterification between carboxylic acids and alcohols in almost equimolar amounts. The local hydrophobic environment provided by the aryl substituents around the reaction center appears to enable condensation to proceed without the need to remove the water produced.…”

Section: Introductionmentioning

confidence: 99%

“…We envisioned promoting dehydrative glycosylation in a similar manner. To date, there is just a single report describing an aggregated complex of a N,N-diarylammonium sulfate being used to catalyze dehydrative glycosylation of a reactive benzyl-protected ribose and 1-dodecanol in water [21]. Herein, we disclose a glycosylation reaction driven by water exclusion, which encompasses a microwave-assisted method for direct dehydrative glycosylations of both armed and disarmed saccharides by using diphenylammonium triflate (DPAT) as an efficient and green catalyst.…”

Section: Introductionmentioning

confidence: 99%

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Direct Dehydrative Glycosylation Catalyzed by Diphenylammonium Triflate

Hsu

Lam

et al. 2020

Molecules

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Methods for direct dehydrative glycosylations of carbohydrate hemiacetals catalyzed by diphenylammonium triflate under microwave irradiation are described. Both armed and disarmed glycosyl-C1-hemiacetal donors were efficiently glycosylated in moderate to excellent yields without the need for any drying agents and stoichiometric additives. This method has been successfully applied to a solid-phase glycosylation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct Dehydrative Glycosylation Catalyzed by Diphenylammonium Triflate

Hsu

Lam

et al. 2020

Molecules

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“…Kobayashi et al were the first in 2001 to demonstrate the use of 4‐dodecylbenzenesulfonic acid (DBSA) to act as an acid catalyst in dehydrative esterifications of carboxylic acids using water as solvent . Their results were followed by other reports using similar catalysts capable of working in biphasic or emulsified media, which worked on a similar principle of creating an isolated hydrophobic environment in which the reagents would condense and the produced water molecule would be expulsed upon production . Within this field surfactant (micellar) catalysts are of particular interest as due to their hydrophobic tail and hydrophilic head they are able to either: Form micelles that create isolated hydrophobic environments in which organic reagents can react within an aqueous media , or form reverse micelles that trap the water released from the condensation reaction in hydrophilic pockets, separate from the organic phase of the reaction mixture .…”

Section: Introductionmentioning

confidence: 99%

Effect of water and lipophilic alcohols or amines on the 4‐dodecylbenzenesulfonic acid‐catalyzed esterifications, trans‐esterifications, and amidations

Wallis

Cerny

Lacroux

et al. 2017

Euro J Lipid Sci & Tech

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4‐Dodecylbenzenesulfonic acid (DBSA) was employed in the esterification of oleic acid (OA) and the trans‐esterification of oleic oil (OO) with 1‐butanol as alcohol in the presence of various degrees of excess water. Under these conditions DBSA was found to be a highly active esterification catalyst regardless of excess water content, but was found to be a less effective for trans‐esterification reactions. Lipophilic alcohols of differing straight and branched C3‐6 chains were also tested on mixtures of OA/water (1:1) in DBSA‐catalyzed esterifications; OO/water (1:1) in trans‐esterifications; and OA/OO/water (1:1:1) in simultaneous esterifications and trans‐esterifications. While longer straight chain alcohols generally gave a two‐fold increase in yield of their corresponding alkyl oleates to 80%+, we observed a doubling from 30–50% to 60–95% of alkyl oleate yield for the OO/OA/water mixture. DBSA‐catalyzed amidations of OO and methyl oleate emulsions in water were conducted with 1‐butyl and 1‐heptyl amine where it was found that the more lipophilic the ester moiety the higher the yield of alkyl amide. Practical applications: The practical advantages of DBSA as catalyst are high conversions to the desired product along with its tolerance to high quantities of water, emulsified within the lipid material. A capacity to transform a range of substrates with varying lipophilic character in a range of condensation reactions. In addition, we demonstrate that esterification and trans‐esterification reactions could be performed simultaneous and in the presence of high quantities of water. This is of direct interest to the transformation of waste sources of lipids that often contain a mixture of triglycerides and free fatty acids in various concentrations, emulsified with waste water. Furthermore, we demonstrate that all of the value‐added products/co‐products can be separated by an effective and industrially relevant methodology, including recovery of the DBSA catalyst as well as the water and water soluble co‐products, such as glycerol. A 4‐Dodecylbenzenesulfonic acid (DBSA) is demonstrated to be an effective polyvalent catalyst for the recovery of aqueous emulsified lipids by conversion into value‐added products. DBSA proved to be a polyvalent catalyst showing high activity using a range of substrates, performing esterification, trans‐esterification, and amidations reactions efficiently despite the potential detrimental presence of high water loadings. The commercial incentive of our system is the phase separation of the product mixture into the converted lipids for use as biofuels and glycerol for resale as a fine chemical.

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“…For example, the employment of diarylammonium arenesulfonates 1 and pyrosulfates 2 as dehydrative condensation catalysts and use of p -dodecylbenzenesulfonic acid for catalytic esterification reactions in water were reported. 3 Histidine sulfonamide, 4 N -alkyl-4-boronopyridinium iodide 5 , iodosodilactone 6 , proline 7 and carbenes 8 were also examined as catalysts for promoting esterification reactions.…”

Section: Introductionmentioning

confidence: 99%

Esterification Catalysis by Pyridinium p-Toluenesulfonate Revisited—Modification with a Lipid Chain for Improved Activities and Selectivities

Wang

Liu

et al. 2013

Synthetic Communications

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The lipid analogues of pyridinium p-toluenesulfonate (PPTS) were examined for catalyzing the condensation of an equimolar mixture of carboxylic acids and alcohols under mild conditions without removal of water. Although PPTS is a poor catalyst, the introduction of a lipid chain and nitro group significantly improved the activity of PPTS and led to selectivity at suppressing elimination side reactions of alcohols. 2-Oleamido-5-nitro-pyridinium p-toluenesulfonate (6) is a lead catalyst that promoted various esterification reactions with yields up to 99%.

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Hydrophobic N,N-Diarylammonium Pyrosulfates as Dehydrative Condensation Catalysts under Aqueous Conditions

Cited by 32 publications

References 30 publications

Direct Dehydrative Glycosylation Catalyzed by Diphenylammonium Triflate

Direct Dehydrative Glycosylation Catalyzed by Diphenylammonium Triflate

Effect of water and lipophilic alcohols or amines on the 4‐dodecylbenzenesulfonic acid‐catalyzed esterifications, trans‐esterifications, and amidations

Esterification Catalysis by Pyridinium p-Toluenesulfonate Revisited—Modification with a Lipid Chain for Improved Activities and Selectivities

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