25753-16-6Relevant articles and documents
Organocatalytic Desymmetrisation of Fittig's Lactones: Deuterium as a Reporter Tag for Hidden Racemisation
Spránitz, Péter,Soregi, Petra,Botlik, Bence Béla,Berta, Máté,Soós, Tibor
, p. 1263 - 1272 (2019/02/26)
Highly enantioselective desymmetrisation of Fittig's lactones with alcohols is promoted by bifunctional cinchona squaramides. The reactions were carried out with monodeuterated methanol to detect possible hidden racemisation of the stereogenic centre. Current evidence suggests that racemisation was not a relevant process for most substrates; partial erosion of enantioselectivity was only detected with ortho -substituted aryl derivates. The resultant glutaric acid derivatives possess a scaffold that is common in natural products and the compounds are also useful chiral building blocks for further synthetic endeavours.
One-pot synthesis of thioesters with sodium thiosulfate as a sulfur surrogate under transition metal-free conditions
Liao, Yen-Sen,Liang, Chien-Fu
supporting information, p. 1871 - 1881 (2018/03/23)
In this paper, we report an efficient synthetic method for thioester formation from sodium thiosulfate pentahydrate, organic halides, and aryl anhydrides. In the one-pot two-step reactions developed in this study, sodium thiosulfate was used as the sulfur surrogate for acylation with anhydrides, followed by substitution with organic halides through the in situ generation of thioaroylate. Furthermore, two important organic compounds could be successfully synthesized using our developed method. The advantages of the one-pot two-step reactions are operational simplicity, structurally diverse products with 42%-90% yields, use of relatively low toxic and odourless reagents, and easy applicability to large-scale operation.
Sc(OTf)3-catalyzed synthesis of anhydrides from twisted amides
Liu, Yongmei,Liu, Ruzhang,Szostak, Michal
, p. 1780 - 1785 (2017/03/09)
A novel synthesis of anhydrides from twisted amides is reported. Sc(OTf)3 catalysis in the presence of water is used to synthesize anhydrides in one step from amides without external nucleophiles. Mechanistic studies indicate that the coordination of the catalyst is critical to induce the challenging N-C activation step. This process further highlights the utility of twisted amides in organic synthesis. Notably, the reaction indicates that twisted amides based on the glutarimide scaffold are more reactive than carboxylic acid anhydrides under the developed conditions, which opens the door to controlled sequential catalysis through amide N-C bond cleavage.
Light-enabled synthesis of anhydrides and amides
Mccallum, Terry,Barriault, Louis
, p. 2874 - 2878 (2015/03/30)
Recently, we have demonstrated that the photogeneration of Vilsmeier-Haack reagents is possible using only dimethylformamide (DMF) and tetrabromomethane (CBr4) in the bromination of alcohols. Extending these findings to carboxylic acid substrates has produced a mild and facile approach to the in situ formation of symmetric anhydrides, which were conveniently converted to amide derivatives in a one-pot process. The efficient protocols discussed herein are marked by use of UVA LEDs (365 nm), which have reduced the reaction times and come with a low setup cost.
An effective method for the synthesis of carboxylic esters and lactones using substituted benzoic anhydrides with Lewis acid catalysts
Shiina, Isamu
, p. 1587 - 1599 (2007/10/03)
An efficient mixed-anhydride method for the synthesis of carboxylic esters and lactones using benzoic anhydride having electron withdrawing substituent(s) is developed by the promotion of Lewis acid catalysts. In the presence of a catalytic amount of TiCl2(ClO4)2, various carboxylic esters are prepared in high yields through the formation of the corresponding mixed-anhydrides from 3,5-bis(trifluoromethyl)benzoic anhydride and carboxylic acids. The combined catalyst consisting of TiCl 2(ClO4)2 together with chlorotrimethylsilane functions as an effective catalyst for the synthesis of carboxylic esters from free carboxylic acids and alcohols with 4-(trifluoromethyl)benzoic anhydride. Various macrolactones are prepared from the free ω-hydroxycarboxylic acids by the combined use of 4-(trifluoromethyl)benzoic anhydride and titanium(IV) catalysts together with chlorotrimethylsilane under mild reaction conditions. The lactonization of trimethylsilyl ω-(trimethylsiloxy) carboxylates using 4-(trifluoromethyl)benzoic anhydride is also promoted at room temperature in the presence of a catalytic amount of TiCl 2(ClO4)2. An 8-membered ring lactone, a synthetic intermediate of cephalosporolide D, is successfully synthesized according to this mixed-anhydride method using 4-(trifluoromethyl)benzoic anhydride by the promotion of a catalytic amount of Hf(OTf)4.
A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid
Miyashita, Mitsutomo,Shiina, Isamu,Miyoshi, So,Mukaiyama, Teruaki
, p. 1516 - 1527 (2007/10/02)
In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
The catalytic Friedel-Crafts acylation reaction starting from aromatic compounds and free carboxylic acids (or their trimethylsilyl esters) by promotion of silicon (IV) cationic species via mixed anhydrides
Suzuki,Kitagawa,Mukaiyama
, p. 3729 - 3734 (2007/10/02)
In the presence of active cationic species generated from silicon(IV) chloride and silver perchlorate, carboxylic acids or their trimethylsilyl esters react with p-trifluoromethylbenzoic anhydride to form corresponding mixed anhydrides in situ. Then the catalytic Friedel-Crafts acylation reaction between initially formed mixed anhydrides and coexisted aromatic compounds smoothly proceeds at room temperature to afford the corresponding aromatic ketones in high yields. The above two sequential reactions are effectively promoted by the active silicon(IV) catalyst under mild conditions.
