Synthesis of 3-Substituted 2-Arylpyridines via Cu/Pd-Catalyzed Decarboxylative Cross-Coupling of Picolinic Acids with (Hetero)Aryl Halides
作者:Dagmar Hackenberger、Philip Weber、David C. Blakemore、Lukas J. Goossen
DOI:10.1021/acs.joc.7b00046
日期:2017.4.7
A decarboxylativecross-coupling of 3-substituted picolinic acids with (hetero)arylhalides is presented. In the presence of catalytic Cu2O and Pd(1,5-cyclooctadiene)Cl2 with 2-dicyclohexylphosphino-2′-(N,N-dimethylamino)biphenyl as the ligand, both electron-rich and electron-deficient aryl bromides and chlorides as well as heteroaryl bromides were successfully coupled with various picolinate salts
solvent, an array of xanthenes, thiazole, pyrazine, and pyridazine are compatible with this new arylation approach. The broad substrate scope, mild reaction conditions, and use of water as reaction solvent make this procedure a practical and environmentally friendly method for the synthesis of compounds containing aryl‐heteroaryl motifs.
已经开发出一种高效的可见光促进的N-杂芳烃与芳基重氮盐在水中的“自由基型”偶联。在室温下将反应继续进行的[Ru(联吡啶)3 ]氯2 ⋅ 6 H 2O作为光敏剂,商用灯泡作为光源。在这些反应条件下,吡啶和各种取代的吡啶是有效的底物,仅形成具有不同区域选择性的单取代产物。使用甲酸水溶液作为溶剂,一系列的黄嘌呤,噻唑,吡嗪和哒嗪与这种新的芳基化方法兼容。广泛的底物范围,温和的反应条件以及使用水作为反应溶剂,使得该程序成为合成具有芳基-杂芳基基序的化合物的实用且环境友好的方法。
A Micellar Catalysis Strategy for Suzuki–Miyaura Cross-Couplings of 2-Pyridyl MIDA Boronates: <i>No Copper</i>, in Water, Very Mild Conditions
作者:Nicholas A. Isley、Ye Wang、Fabrice Gallou、Sachin Handa、Donald H. Aue、Bruce H. Lipshutz
DOI:10.1021/acscatal.7b03241
日期:2017.12.1
Suzuki-Miyaura (SM) cross-couplings of 2-pyridyl MIDA boronates can be successfully carried out in the complete absence of copper by attenuation of the Lewis basicity associated with the pyridyl nitrogen using selected substituents (e.g., fluorine or chlorine) on the ring. This strategy imparts additional synthetic options compared with existing approaches based on the use of Lewis acids or N-oxides. Thus, access to highly valued 2-substituted pyridyl rings via an initial Suzuki-Miyaura coupling can be followed by dehalogenation, SNAr reactions, or a second SM coupling to arrive at 2,6-disubstituted pyridyl arrays, all run in a single pot, enabled by micellar catalysis in water. Accessing targets within drug-like space is demonstrated in a four-step, one-pot sequence. Computational data suggest that the major role being played by electron-withdrawing substituents in promoting these cross-couplings without the need for copper is to slow the rates of protodeboronation of intermediate 2-pyridylboronic acids.
Cobalt-doped iron-based coordination polymer catalyst with unique shell-shaped agglomerate for enhancing the reaction activity of Kumada-coupling