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119 results on '"Yang, Xu‐Heng"'

33. Metal-Free [4+2] Annulation of Arylalkynes with tert-Butyl Nitrite through C(sp2)--H Oxidation to Assemble Benzo[e][1,2]oxazin-4-ones.

Author

Yang, Xu ‐ Heng, Song, Ren ‐ Jie, and Li, Jin ‐ Heng

Subjects
*ANNULATION, *ALKYNE synthesis, *CARBON-hydrogen bonds, *NITRITES, *FREE radical reactions, *ADDITION reactions
Abstract

A metal-free radical-mediated [4+2] annulation of internal arylalkynes with tert-butyl nitrite (t-BuONO) is presented for the synthesis of benzo[e][1,2]oxazin-4-ones through the addition of t-BuONO across the CŽ≡C triple bond, hydration, isomerization and aromatic C(sp2)--H oxidation cascades. The 18O-labeling experiment shows that two oxygen atoms in the product system are from water. [ABSTRACT FROM AUTHOR]

Published
2015
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44. Nitrative Spirocyclization Mediated by TEMPO: Synthesis of Nitrated Spirocycles from N-Arylpropiolamides, tert-Butyl Nitrite and Water.

Author

Yang, Xu ‐ Heng, Ouyang, Xuan ‐ Hui, Wei, Wen ‐ Ting, Song, Ren ‐ Jie, and Li, Jin ‐ Heng

Subjects
*ORGANIC synthesis, *AMIDES, *ALKYNES, *CHEMICAL bonds, *BUTYL nitrite
Abstract

A new method for the nitrative spirocyclization of alkynes is described. This method involves the oxidative difunctionalization of alkynes initiated by a radical attack pathway using t-BuONO ( tert-butyl nitrite) combined with water as the nitro source and TEMPO [(2,2,6,6-tetramethyl-piperidin-1-yl)oxyl] as the initiator, and it represents a new example of oxidative alkyne difunctionalization via the formation of CN/CC bonds for the assembly of nitroalkene unit-containing spirocycles. [ABSTRACT FROM AUTHOR]

Published
2015
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45. (Diacetoxyiodo)benzene-Mediated Oxygenation of Benzylic C(sp3)-H Bonds with N-Hydroxyamides at Room Temperature.

Author

Qian, Peng‐Cheng, Liu, Yu, Song, Ren‐Jie, Hu, Ming, Yang, Xu‐Heng, Xiang, Jian‐Nan, and Li, Jin‐Heng

Subjects
OXIDATION, ACETAMIDE, OXIDATIVE coupling, CHEMICAL bonds, ELECTROPHILES
Abstract

A new, metal-free method for the formation of C(sp3)-O bonds was established by PhI(OAc)2-mediated oxygenation of benzylic C(sp3)-H bonds with N-hydroxyamides at room temperature, in which the C(sp3)-H oxidation is activated by a polyflurophenylamide group. [ABSTRACT FROM AUTHOR]

Published
2015
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46. Oxidative Coupling of Alkenes with Aldehydes and Hydroperoxides: One-Pot Synthesis of 2,3-Epoxy Ketones.

Author

Wei, Wen ‐ Ting, Yang, Xu ‐ Heng, Li, Hai ‐ Bing, and Li, Jin ‐ Heng

Subjects
*OXIDATIVE coupling, *KETONE synthesis, *ALKENE synthesis, *ALDEHYDE synthesis, *HYDROPEROXIDES
Abstract

A new transition metal-free oxidative coupling of unactivated terminal alkenes with aldehydes and hydroperoxides in the presence of 10 mol% potassium tert-butanolate ( t-BuOK) is described thereby realizing trifunctionalization of alkenes toward 2,3-epoxy ketones. This method is applicable to a wide range of aldehydes, including aryl and alkyl aldehydes, with excellent functional group tolerance, and provides for the one-step assembly of 2,3-epoxy ketones. [ABSTRACT FROM AUTHOR]

Published
2015
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47. Room-Temperature Palladium-Catalyzed Intramolecular Oxidative Aminocarbonylation of Vinylic C(sp2)-H Bonds with Amines and CO.

Author

Yang, Xu‐Heng, Li, Kai, Song, Ren‐Jie, and Li, Jin‐Heng

Subjects
*PALLADIUM, *CLASS B metals, *CARBONYLATION, *CHEMICAL reactions, *AMINES
Abstract

A new, mild route to access 3-methyleneindolin-2-ones is presented that proceeds through a room-temperature, palladium-catalyzed intramolecular oxidative aminocarbonylation of alkenes with amines and CO. This method represents a new aminocarbonylation strategy by employing an oxidative functionalization of a vinyl C(sp2)-H bond. [ABSTRACT FROM AUTHOR]

Published
2014
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48. Oxidative Cleavage of the Carbon—Carbon σ-Bond Using Reusable Copper on Iron

Author

Song, Ren‐Jie, Liu, Yu, Hu, Rui‐Xiang, Liu, Yan‐Yun, Wu, Ji‐Cheng, Yang, Xu‐Heng, and Li, Jin‐Heng

Abstract

An efficient and resuble copper on iron catalyst has been prepared for the cleavage of the carbon‐carbon σ‐bond in α‐aminocarbonyl compounds leading to the corresponding formylamides and acids with a maximal TON of up to 51,000. It is noteworthy that the copper on iron catalyst can be easily separated from the reaction mixture, and retains its activity after several reuses.

Published
2011
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49. ChemInform Abstract: Metal-Free [4 + 2] Annulation of Arylalkynes with tert-Butyl Nitrite Through C(sp2)-H Oxidation to Assemble Benzo[e][1,2]oxazin-4-ones.

Author

Yang, Xu‐Heng, Song, Ren‐Jie, and Li, Jin‐Heng

Subjects
*ALKYNE synthesis, *BENZOXAZINONES, *ANNULATION
Abstract

A metal-free radical-mediated [4+2] annulation of internal arylalkynes with tert-butyl nitrite is presented for the synthesis of benzoxazinones through the addition of t-BuONO across the CC triple bond, hydration, isomerization, and aromatic C(sp2)-H oxidation cascades. [ABSTRACT FROM AUTHOR]

Published
2016
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50. ChemInform Abstract: Oxidative Coupling of Alkenes with Amides Using Peroxides: Selective Amide C(sp3)-H versus C(sp2)-H Functionalization.

Author

Yang, Xu‐Heng, Wei, Wen‐Ting, Li, Hai‐Bing, Song, Ren‐Jie, and Li, Jin‐Heng

Subjects
*OXIDATIVE coupling, *ALKENES, *AMIDES, *PEROXIDES, *CHEMOSELECTIVITY
Abstract

Mono- and difunctionalization of a broad scope of non-activated alkenes is achieved with excellent chemoselectivities by a new oxidative coupling method. [ABSTRACT FROM AUTHOR]

Published
2015
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