A Metal-Free Amination of Benzoxazoles – The First Example of an Iodide-Catalyzed Oxidative Amination of Heteroarenes
作者:Tanja Froehr、Christian P. Sindlinger、Ulrich Kloeckner、Peter Finkbeiner、Boris J. Nachtsheim
DOI:10.1021/ol201439t
日期:2011.7.15
An efficient transition-metal-free amination of benzoxazoles has been developed. With catalytic amounts of tetrabutylammoniumiodide (TBAI), aqueous solutions of H2O2 or TBHP as co-oxidant and undermild reaction conditions, highly desirable 2-aminobenzoxazoles were isolated in excellent yields of up to 93%. First mechanistic experiments indicate the in situ iodination of the secondary amine as the
已经开发出有效的无过渡金属苯并恶唑胺化的方法。用催化量的四丁基碘化铵(TBAI),H 2 O 2或TBHP水溶液作为助氧化剂,并在温和的反应条件下,以高达93%的优异收率分离出了非常理想的2-氨基苯并恶唑。最初的机械实验表明,仲胺的原位碘化是假定的活化方式。
Visible-light-initiated photo-oxidative cyclization of phenolic amidines using CBr4 – A metal free approach to 2-aminobenzoxazoles
作者:Twinkle Keshari、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1039/c3ra46314a
日期:——
A mild and efficient one-pot operation for the amination of benzoxazoles has been achieved via ring opening of benzoxazoles followed by visible-light-mediated aerobic photo-oxidative cyclization of the resulting o-phenolic amidines using CBr4 as a mild oxidant. The protocol is economical and environmentally benign as it utilizes visible light and does not require any photosensitizers, additives, heating
Room-Temperature Amination of Chloroheteroarenes in Water by a Recyclable Copper(II)-Phosphaadamantanium Sulfonate System
作者:Udaysinh Parmar、Dipesh Somvanshi、Santosh Kori、Aman A. Desai、Rambabu Dandela、Dilip K. Maity、Anant R. Kapdi
DOI:10.1021/acs.joc.1c00845
日期:2021.7.2
Buchwald–Hartwig amination of chloroheteroarenes has been a challenging synthetic process, with very few protocols promoting this important transformation at ambient temperature. The current report discusses about an efficient copper-based catalyticsystem (Cu/PTABS) for the amination of chloroheteroarenes at ambient temperature in water as the sole reaction solvent, a combination that is first to
Synthesis of 2-Aminobenzoxazoles Using Tetramethyl Orthocarbonate or 1,1-Dichlorodiphenoxymethane
作者:Christopher L. Cioffi、John J. Lansing、Hamza Yüksel
DOI:10.1021/jo1017052
日期:2010.11.19
The synthesis of 2-aminobenzoxazoles can be readily achieved by two versatile, one-pot procedures utilizing commercially available tetramethyl orthocarbonate or 1,1-dichlorodiphenoxymethane, an amine, and an optionally substituted 2-aminophenol. The reactions were conducted under mild conditions and provided 2-aminobenzoxazoles in modest to excellent yields. A variety of amines and substituted 2-aminophenols