701-53-1Relevant academic research and scientific papers
Rapid and column-free syntheses of acyl fluorides and peptides usingex situgenerated thionyl fluoride
Lee, Cayo,Sammis, Glenn M.,Thomson, Brodie J.
, p. 188 - 194 (2021/12/31)
Thionyl fluoride (SOF2) was first isolated in 1896, but there have been less than 10 subsequent reports of its use as a reagent for organic synthesis. This is partly due to a lack of facile, lab-scale methods for its generation. Herein we report a novel protocol for theex situgeneration of SOF2and subsequent demonstration of its ability to access both aliphatic and aromatic acyl fluorides in 55-98% isolated yields under mild conditions and short reaction times. We further demonstrate its aptitude in amino acid couplings, with a one-pot, column-free strategy that affords the corresponding dipeptides in 65-97% isolated yields with minimal to no epimerization. The broad scope allows for a wide range of protecting groups and both natural and unnatural amino acids. Finally, we demonstrated that this new method can be used in sequential liquid phase peptide synthesis (LPPS) to afford tri-, tetra-, penta-, and decapeptides in 14-88% yields without the need for column chromatography. We also demonstrated that this new method is amenable to solid phase peptide synthesis (SPPS), affording di- and pentapeptides in 80-98% yields.
Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles
Barbasiewicz, Micha?,Tryniszewski, Micha?
, (2021/11/30)
A series of acyl fluorides was synthesized at 100 mmol scale using phase-transfer-catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at room temperature, followed by extraction and distillation. Isolated acyl fluorides (usually 7-20 g) display excellent purity and can be transformed into sterically hindered amides and esters when treated with lithium amide bases and alkoxides under mild conditions.
Metal-free approach for hindered amide-bond formation with hypervalent iodine(iii) reagents: application to hindered peptide synthesis
Lee, Hyo-Jun,Huang, Xiao,Sakaki, Shigeyoshi,Maruoka, Keiji
, p. 848 - 855 (2021/02/09)
A new bio-inspired approach is reported for amide and peptide synthesis using α-amino esters that possess a potential activating group (PAG) at the ester residue. To activate the ester functionality under mild metal-free conditions, we exploited the facile dearomatization of phenols with hypervalent iodine(iii) reagents. Using a pyridine-hydrogen fluoride complex, highly reactive acyl fluoride intermediates can be successfully generated, thereby allowing for the smooth formation of sterically hindered amides and peptides from bulky amines and α-amino esters, respectively.
Cooperative NHC/Photoredox Catalyzed Ring-Opening of Aryl Cyclopropanes to 1-Aroyloxylated-3-Acylated Alkanes
Daniliuc, Constantin G.,Studer, Armido,Zuo, Zhijun
supporting information, p. 25252 - 25257 (2021/10/29)
Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization of aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The cascade works on monosubstituted cyclopropanes that are in contrast to the heavily investigated donor–acceptor cyclopropanes more challenging to be difunctionalized. The key step is a radical/radical cross coupling of a benzylic radical generated in the photoredox catalysis cycle with a ketyl radical from the NHC catalysis cycle. The transformation features metal-free reaction conditions and tolerates a diverse range of functionalities.
Fluorination method
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Paragraph 0081-0125, (2021/01/12)
In order to overcome the problems of high cost and low stability of the existing fluorination reagents for preparing acyl fluoride, sulfonyl fluoride and phosphoryl fluoride compounds, the invention provides a fluorination method, which comprises the following operation steps of: adding a fluorination reagent into a substrate, wherein the fluorination reagent comprises cations M and anions, the anions are selected from one or more of perfluoropolyether chain carboxylic acid anions as shown in the specification: CF3(OCF2)nCO2, wherein n is selected from 1-10; the substrate comprises a carboxylic acid compound, a sulfonic acid compound, a phosphoric acid compound and a phosphine oxide compound; and carrying out fluorination reaction to obtain acyl fluoride, sulfonyl fluoride and phosphoryl fluoride products. According to the fluorination method provided by the invention, the perfluoropolyether chain carboxylate is used as a fluorination reagent, so that the dehydroxylation fluorination reaction of the carboxylic acid compound, the sulfonic acid compound and the phosphoric acid compound and the fluorination reaction of the phosphine oxide compound are realized, the product yield isrelatively high, and the fluorination method has relatively good universality for different substrates.
METHOD AND REAGENT FOR DEOXYFLUORINATION
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Paragraph 0111-0112; 0114-0115; 0126, (2021/05/29)
A safe, simple, and selective method and reagent for deoxyfluorination is disclosed. With the method and reagent disclosed herein, organic compounds such as carboxylic acids, carboxylates, carboxylic acid anhydrides, aldehydes, and alcohols can be fluorinated by using the most common nucleophilic fluorinating reagents and electron deficient fluoroarenes as mediators under mild conditions, giving corresponding fluoroorganic compounds in excellent yield with a wide range of functional group compatibility and easy product purification. For example, directly utilizing KF for deoxyfluorination of carboxylic acids provides the most economical and the safest pathway to access acyl fluorides, key intermediates for syntheses of peptide, amide, ester, and dry fluoride salts.
Deoxyfluorination of Carboxylic, Sulfonic, Phosphinic Acids and Phosphine Oxides by Perfluoroalkyl Ether Carboxylic Acids Featuring CF2O Units
Zhao, Shiyu,Guo, Yong,Su, Zhaoben,Wu, Chengying,Chen, Wei,Chen, Qing-Yun
supporting information, p. 1225 - 1232 (2021/05/04)
The deoxyfluorination of carboxylic, sulfonic, phosphinic acids and phosphine oxides is a fundamentally important approach to access acyl fluorides, sulfonyl fluorides and phosphoric fluorides, thus the development of inexpensive, stable, easy-to-handle, versatile, and efficient deoxyfluorination reagents is highly desired. Herein, we report the use of potassium salts of perfluoroalkyl ether carboxylic acids (PFECA) featuring CF2O units as deoxyfluorination reagents, which are generated mainly as by-products in the manufacture of hexafluoropropene oxide (HFPO). The synthesis of acyl fluorides, sulfonyl fluorides and phosphoric fluorides can be realized via carbonic difluoride (COF2) generated in situ from thermal degradation of the PFECA salt.
Deoxyfluorination of Carboxylic Acids with KF and Highly Electron-Deficient Fluoroarenes
Mao, Siyu,Kramer, Jordan H.,Sun, Haoran
, p. 6066 - 6074 (2021/05/29)
A deoxyfluorination reaction of carboxylic acids using potassium fluoride (KF) and highly electron-deficient fluoroarenes is reported here, giving acyl fluorides in moderate to excellent yield (57-92% based on NMR integration and 34-95% for isolated examples).
Deoxyfluorination of Carboxylic Acids with CpFluor: Access to Acyl Fluorides and Amides
Wang, Xiu,Wang, Fei,Huang, Fengfeng,Ni, Chuanfa,Hu, Jinbo
supporting information, p. 1764 - 1768 (2021/03/03)
3,3-Difluoro-1,2-diphenylcyclopropene (CpFluor), a bench-stable fluorination reagent, has been developed in the deoxyfluorination of carboxylic acids to afford various acyl fluorides. This all-carbon-based fluorination reagent enabled the efficient transformation of (hetero)aryl, alkyl, alkenyl, and alkynyl carboxylic acids to the corresponding acyl fluorides under the neutral conditions. This deoxyfluorination method was featured by the synthesis of acyl fluorides with in-situ formed CpFluor, as well as the one-pot amidation reaction of carboxylic acids via in-situ formed acyl fluorides.
Carboxylic Acid Deoxyfluorination and One-Pot Amide Bond Formation Using Pentafluoropyridine (PFP)
Brittain, William D. G.,Cobb, Steven L.
supporting information, p. 5793 - 5798 (2021/08/01)
This work describes the application of pentafluoropyridine (PFP), a cheap commercially available reagent, in the deoxyfluorination of carboxylic acids to acyl fluorides. The acyl fluorides can be formed from a range of acids under mild conditions. We also demonstrate that PFP can be utilized in a one-pot amide bond formation via in situ generation of acyl fluorides. This one-pot deoxyfluorination amide bond-forming reaction gives ready access to amides in yields of ≤94%.
