1173294-94-4Relevant articles and documents
Palladium-catalyzed decarboxylative, decarbonylative and dehydrogenative C(sp2)-H acylation at room temperature
Hossian, Asik,Manna, Manash Kumar,Manna, Kartic,Jana, Ranjan
, p. 6592 - 6603 (2017/08/16)
Over the past few decades, an impressive array of C-H activation methodology has been developed for organic synthesis. However, due to the inherent inertness of the C-H bonds (e.g. ～110 kcal mol-1 for the cleavage of C(aryl)-H bonds) harsh reaction conditions have been realized to overcome high energetic transition states resulting in a limited substrate scope and functional group tolerance. Therefore, the development of mild C-H functionalization protocols is in high demand to exploit the full potential of the C-H activation strategy in the synthesis of a complex molecular framework. Although, electron-rich substrates undergo electrophilic metalation under relatively mild conditions, electron-deficient substrates proceed through a rate-limiting C-H insertion under forcing conditions at high temperature. In addition, a stoichiometric amount of toxic silver salt is frequently used in palladium catalysis to facilitate the C-H activation process which is not acceptable from the environmental and industrial standpoint. We report herein, a Pd(ii)-catalyzed decarboxylative C-H acylation of 2-arylpyridines with α-ketocarboxylic acids under mild conditions. The present protocol does not require stoichiometric silver(i) salts as additives and proceeds smoothly at ambient temperature. A novel decarbonylative C-H acylation reaction has also been accomplished using aryl glyoxals as acyl surrogates. Finally, a practical C-H acylation via a dehydrogenative pathway has been demonstrated using commercially available benzaldehydes and aqueous hydroperoxides. We also disclose that acetonitrile solvent is optimal for the acylation reaction at room temperature and has a prominent role in the reaction outcome. Control experiments suggest that the acylation reaction via decarboxylative, decarbonylative and dehydrogenative proceeds through a radical pathway. Thus we disclose a practical protocol for the sp2 C-H acylation reaction.
Pd(ii)-catalysed o-aroylation of directing arenes using terminal aryl alkenes and alkynes
Khatun, Nilufa,Banerjee, Arghya,Santra, Sourav K.,Behera, Ahalya,Patel, Bhisma K.
, p. 54532 - 54538 (2015/01/16)
A substrate-directed Pd-catalysed o-aroylation strategy has been demonstrated using new aroyl surrogates viz. terminal aryl alkenes and alkynes in the presence of TBHP. By a subtle change in catalyst from Cu to Pd, a differential selectivity is observed.
Palladium-catalyzed acylation of sp2 C-H bond: Direct access to ketones from aldehydes
Jia, Xiaofei,Zhang, Shouhui,Wang, Wenhui,Luo, Fang,Cheng, Jiang
supporting information; experimental part, p. 3120 - 3123 (2009/12/06)
A palladium-catalyzed direct access to ketones from aldehydes via C-H cleavage of arenes is described. The procedure utilizes air as a clean and free terminal oxidant.
