Palladium-Catalyzed Decarboxylative Couplings of 2-(2-Azaaryl)acetates with Aryl Halides and Triflates
作者:Rui Shang、Zhi-Wei Yang、Yan Wang、Song-Lin Zhang、Lei Liu
DOI:10.1021/ja107103b
日期:2010.10.20
Pd-catalyzed decarboxylative cross-couplings of 2-(2-azaaryl)acetates with arylhalides and triflates have been discovered. This reaction is potentially useful for the synthesis of some functionalized pyridines, quinolines, pyrazines, benzoxazoles, and benzothiazoles. Theoretical analysis shows that the nitrogen atom at the 2-position of the heteroaromatics directly coordinates to Pd(II) in the decarboxylation
Elemental Sulfur-Promoted Oxidative Rearranging Coupling between o-Aminophenols and Ketones: A Synthesis of 2-Alkyl benzoxazoles under Mild Conditions
作者:Thanh Binh Nguyen、Pascal Retailleau
DOI:10.1021/acs.orglett.7b01775
日期:2017.7.21
In the presence of N-methylpiperidine, elemental sulfur was found to act as excellent oxidant in promoting oxidative rearranging coupling between o-aminophenols and ketones. A wide range of 2-alkylbenzoxazoles was obtained under mild conditions.
One-Pot Synthesis of 2-Substituted Benzoxazoles Directly from Carboxylic Acids
作者:Dinesh Kumar、Santosh Rudrawar、Asit K. Chakraborti
DOI:10.1071/ch08193
日期:——
Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ fromcarboxylicacids. Aryl, heteroaryl, and arylalkyl carboxylicacids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents
A unique α-amination approach using various anilines has been developed for arylacetic acids via adaptation as benzazoles. The reaction proceeds through a single electron transfer mechanism utilizing an iron-based catalyst system to access α-(N-arylamino)acetic acid equivalents. Modification of approved drugs, facile cleavage of the benzazole auxiliary, and tolerance of amide linkage forming conditions
Pd<sup>II</sup>-Catalyzed methoxylation of C(sp<sup>3</sup>)–H bonds adjacent to benzoxazoles and benzothiazoles
作者:Jogendra Kumar、Aniket Gupta、Sukalyan Bhadra
DOI:10.1039/c9ob00337a
日期:——
The Pd(OAc)2/PhI(OAc)2 catalyst system promotes the highly regioselective dehydrogenative methoxylation of a C(sp3)–H bond adjacent to benzoxazole and benzothiazole rings. The title transformation constitutes the first example of a Pd-catalyzed C(sp3)–H activating methoxylation at the proximal-selective α-position with regard to a directing auxiliary and provides expedient access to an important class