کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1327097 977462 2008 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Direct arylation of oxazole and benzoxazole with aryl or heteroaryl halides using a palladium–diphosphine catalyst
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Direct arylation of oxazole and benzoxazole with aryl or heteroaryl halides using a palladium–diphosphine catalyst
چکیده انگلیسی

Through the use of PdCl(dppb)(C3H5) as a catalyst, a range of aryl bromides and chlorides undergoes coupling via C–H bond activation/functionalization reaction with oxazole or benzoxazole in good yields. This air-stable catalyst can be used at low loadings with several substrates. Surprisingly, better results in terms of substrate/catalyst ratio were obtained in several cases using electron-excessive aryl bromides than with the electron-deficient ones. This seems to be mainly due to the relatively low thermal stability of some of the 2-arylbenzoxazoles formed with electron-deficient aryl halides. With these substrates, in order to obtain higher yields of product, the reactions had to be performed at a lower temperature (100–120 °C) using a larger amount of catalyst. On the other hand, in the presence of the most stable products, the reactions were performed at 150 °C using as little as 0.2 mol% catalyst. Arylation of benzoxazole with heteroaryl bromides also gave the coupling products in moderate to high yields using 0.2–5 mol% catalyst. With this catalyst, electron-deficient aryl chloride such as 4-chlorobenzonitrile, 4-chloroacetophenone or 2-chloronitrobenzene have also been used successfully.

Through the use of PdCl(dppb)(C3H5) as a catalyst, a range of aryl bromides and chlorides undergoes coupling via C–H bond activation/functionalization reaction with benzoxazole in good yields. This air-stable catalyst can be used at low loadings with several substrates.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Organometallic Chemistry - Volume 693, Issue 1, 1 January 2008, Pages 135–144
نویسندگان
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