Desulfinative palladium‐catalyzed cross‐coupling of arylsulfonyl hydrazides with aryl bromides under air
作者:Qingling Liu、Bo Yang
DOI:10.1002/aoc.5140
日期:2019.10
A highly efficient and mild palladium‐catalyzed cross‐coupling of arylsulfonyl hydrazides and aryl bromides for the selective synthesis of unsymmetrical biaryls has been developed. This methodology has the advantages of easily accessible starting materials, functional group tolerance and a wide range of substrates, which providerapidaccess to biaryls derivatives. In this protocol, abundant and stable
A bulky carboxylic acid bearing one 1-adamantylmethyl and two methyl substituents at the α-position is demonstrated to work as an efficient carboxylate ligand source in Pd-catalyzed intermolecular C(sp2)–H bond arylation reactions.
The direct functionalization of C–H bonds has drawn the attention of chemists for almost a century. C–H activation has mainly been achieved through four metal-mediated pathways: oxidative addition, electrophilic substitution, σ-bond metathesis and metal-associated carbene/nitrene/oxo insertion. However, the identification of methods that do not require transition-metal catalysts is important because
近一个世纪以来,C-H键的直接官能化引起了化学家的关注。C-H 活化主要通过四种金属介导的途径实现:氧化加成、亲电取代、σ-键复分解和金属相关的卡宾/氮烯/氧代插入。然而,确定不需要过渡金属催化剂的方法很重要,因为涉及这种催化剂的方法通常很昂贵。另一个优点是可以避免从产品中去除金属杂质的要求,这是药物化合物合成中的一个重要问题。在这里,我们描述了芳基碘化物/溴化物与芳烃的 C-H 键之间的交叉偶联的鉴定,该交叉偶联仅由 1,10-菲咯啉作为催化剂在 KO t- Bu 作为碱存在下介导. 这种明显不含过渡金属的工艺提供了一种实现直接 C-H 功能化的新策略。
A macrocyclic aromatic pyridone pentamer as a highly efficient organocatalyst for the direct arylations of unactivated arenes
A macrocyclic aromatic pyridone pentamer was shown to catalyze highly efficient transition-metal-free arylations of unactivated aromatic C-H bonds with aryl iodides and bromides in the presence of potassium tert-butoxide.
electron-rich O atoms for potassium binding, can serve as a highly efficient organocatalyst for catalyzing transition-metal-free arylations of unactivated aromatic C–H bonds with aryl halides in the presence of t-BuOK. A wide range of aryl iodides could be cross-coupled with unactivatedarenes in moderate to excellent yields. The experiments using radical-scavenging reagents confirm the participation of radicals