- Visible-Light-Induced Transition-Metal-Free Nitrogen-Centered Radical Strategy for the Synthesis of 2-Acylated 9 H-Pyrrolo[1,2- a]indoles
-
A convenient and efficient visible-light-induced tandem acylation/cyclization of N-propargylindoles with aryl- or alkyl-substituted acyl oxime esters for the synthesis of 2-acyl-substituted 9H-pyrrolo[1,2-a]indoles under transition-metal-free conditions, which proceeds via nitrogen-centered radical-mediated cleavage of the C-C σ-bond in acyl oxime esters, is established. The aryl or alkyl acyl radicals, which come from acyl oxime esters, attack the C-C triple bonds in N-propargylindoles and then go through intramolecular cyclization/isomerization.
- Yu, Wen-Qin,Xie, Jun,Chen, Zan,Xiong, Bi-Quan,Liu, Yu,Tang, Ke-Wen
-
p. 13720 - 13733
(2021/10/01)
-
- Synthesis of Acyl Fluorides via DAST-Mediated Fluorinative C-C Bond Cleavage of Activated Ketones
-
A new protocol for preparation of acyl fluorides was developed by recognizing activated ketones as starting materials. The method provides a different scope compared with previously reported methods that employ carboxylic acids as substrates. A working hypothesis of pull-and-push-driven fluorinative C-C bond cleavage was successfully demonstrated by the simple addition of diethylaminosulfur trifluoride (DAST) derivatives to α-oximinoketones. The designed reaction system led to a highly efficient and chemoselective reaction. The wide availability of the ketones allowed for a range of synthetically useful aryloyl and aliphatic acyl fluorides including those containing chiral skeletons. The method is mild, fast, scalable, and potentially one-pot operative.
- Kim, Danhee,Lim, Hee Nam
-
supporting information
p. 7465 - 7469
(2020/10/09)
-
- Photocatalytic C-C Bond Activation of Oxime Ester for Acyl Radical Generation and Application
-
A unified strategy to generate acyl radical from oxime ester via selective C-C bond activation is reported. Under visible-light irradiation, single-electron transfer from fac-Ir(ppy)3 to related oxime takes place followed by a fast β-fragment of C-C bond to yield aryl and aliphatic acyl radicals, subsequently captured by diverse Michael acceptors. More interestingly, the single-electron transfer enables coupling with energy transfer of the excited fac-Ir(ppy)3 via enone intermediate formed in situ for cyclobutane formation.
- Fan, Xiuwei,Lei, Tao,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
-
supporting information
p. 4153 - 4158
(2019/06/08)
-
- Nitrosocarbonyl-Henry and Denitration Cascade: Synthesis of α-Ketoamides and α-Keto Oximes
-
An unprecedented Henry reaction of in situ generated nitrosocarbonyl intermediates and concomitant denitration cascade has been developed. The reaction is catalyzed by organic base at room temperature offering α-ketoamides, a demanding scaffold for drug discovery, in high yields. An alteration of substitution pattern also produced α-keto oximes, a high-value synthon. The protocol features operational simplicity and broad substrate scope.
- Reddy, Mallu Kesava,Mallik, Sumitava,Ramakrishna, Isai,Baidya, Mahiuddin
-
supporting information
p. 1694 - 1697
(2017/04/11)
-
- Functionalized α-oximinoketones as building blocks for the construction of imidazoline-based potential chiral auxiliaries
-
Functionalized α-oximinoketones with β-alkoxy, β-alkyl, and β-sulfenyl groups were used as efficient synthons for the preparation of chiral 1-acyl-4-imidazolin-2-ones and 1-acylimidazolidin-2-ones. For the preparation of the former heterocycles, α-oximinoketones were transformed into their respective imidazole N-oxides by neutral treatment with a chiral triazine, followed by reaction with acetic or propionic anhydrides to furnish the desired chiral 1-acetyl- or 1-propionyl-4-imidazolin-2-ones in moderate overall yields. Upon palladium hydroxide-catalyzed hydrogenation, these series were converted into their corresponding 1-acylimidazolidin-2-ones in high diastereoisomeric ratios. Thus, these novel chiral 1-acetyl- and 1-propionyl-imidazolidin-2-ones were obtained with a variety of alkyl groups at the C-4 and C-5 positions of the heterocycle, through a three-step methodology, and can be applied as new potential chiral auxiliaries.
- Gutiérrez, Rsuini U.,Rebollar, Araceli,Bautista, Rafael,Pelayo, Vanessa,Várgas, José Luis,Montenegro, Mabel M.,Espinoza-Hicks, Carlos,Ayala, Francisco,Bernal, Pablo M.,Carrasco, Cuauhtemoc,Zepeda, L. Gerardo,Delgado, Francisco,Tamariz, Joaquín
-
p. 230 - 246
(2015/03/04)
-
- Beckmann rearrangement of α-oximinoketones
-
The Beckmann rearrangement of α-oximinoketones gives benzoic acids as chief isolable products. Both first order and second order Beckmann rearrangements have been observed. The occurrence of first order Beckmann rearrangement in these oximinocarbonyl compounds is confirmed through the identification of the products obtained.
- Kumar, B. N. Hitesh,Prakasam,Srinivasan,Arabindoo, Bhanumathi,Ramana
-
p. 963 - 965
(2008/12/23)
-
- Synthesis and application of a novel coupling reagent, ethyl 1-hydroxy- 1H-1,2,3-triazole-4-carboxylate
-
An optimal coupling reagent, ethyl 1-hydroxy-1H-1,2,3-triazole-4- carboxylate (HOCt), has been designed and synthesised for application to solid phase peptide synthesis using Fmoc chemistry. It is used in combination with carbodiimide reagents, has very high coupling efficiency, and does not absorb at 302nm, thus allowing real-time monitoring of each coupling cycle. Its applications in the synthesis of endothelin analogues and difficult sequences are also discussed.
- Jiang, Lu,Davison, Amanda,Tennant, George,Ramage, Robert
-
p. 14233 - 14254
(2007/10/03)
-
- Chelator compositions comprising oxime compounds
-
The present invention involves photoprotective compositions which are useful for topical application to prevent damage to skin caused by acute or chronic exposure to ultraviolet light comprising chelating agents having the formula STR1 wherein --R1/
- -
-
-