We have developed an efficient Pd‐catalyzed directed C—H bromination protocol, in which dimethyl sulfoxide (DMSO) is employed as oxidant with hydrobromic acid aqueous solution (HBr(aq)) as bromide source. The DMSO/HBr(aq) system, which is novelly and efficiently utilized in transition‐metal catalyzed C—H activation, illustrates its practicability by the operational simplicity, inexpensive and readily
Hypercrosslinked Polymer Platform-Anchored Single-Site Heterogeneous Pd–NHC Catalysts for Diverse C–H Functionalization
作者:Tanmoy Mandal、Moumita Mondal、Joyanta Choudhury
DOI:10.1021/acs.organomet.1c00182
日期:2021.8.9
new class of hypercrosslinked polymer (HCP) platform-anchored single-site heterogenized Pd–NHC catalysts for multipurpose C–H functionalization reactions. This new class is represented by a set of three catalysts, viz., HCP-B-MeNHC-Pd, HCP-B-BnNHC-Pd, and HCP-TPM-MeNHC-Pd, having a variation on the structural feature of the anchoring polymeric platform. All three catalysts were fully characterized via
我们展示了一类新的超交联聚合物(HCP)平台锚定的单点异质化 Pd-NHC 催化剂,用于多用途 C-H 功能化反应。这一新类别由一组三种催化剂代表,即HCP-B- Me NHC-Pd、HCP-B- Bn NHC-Pd和HCP-TPM- Me NHC-Pd,在结构特征上有变化锚定聚合物平台。所有三种催化剂都通过各种固态表征和分析技术(如 X 射线光电子能谱、13C 交叉极化魔角自旋核磁共振、场发射扫描电子显微镜、能量色散 X 射线分析、热重分析和电感耦合等离子体-光发射光谱法。三种经常使用且非常有用的 C-H 官能化反应,即 C-H 卤化、乙酰氧基化和芳基化,用新催化剂进行了测试,发现它们具有高度的相容性和成功性。使用HCP-TPM- Me NHC-Pd在催化剂的作用下,卤化、乙酰氧基化和芳基化反应的官能化产物的产率分别高达 85%、75% 和 70%。这种新系统提供了诸如增强的活性、异质性和可回收性等苛刻的特性,使其成为非均相
Sodium Halides as Halogenating Reagents: Rhodium(III)-Catalyzed Versatile and Practical Halogenation of Aryl Compounds
作者:Panpan Zhang、Liang Hong、Guofeng Li、Rui Wang
DOI:10.1002/adsc.201400590
日期:2015.2.9
AbstractWe report a concise, versatile and practical method for the ortho‐chlorination, ortho‐bromination and ortho‐iodination of aryl compounds. The significant advantage of this transformation is the creation of the carbon‐halogen bond by use of readily available and cheap halide salts as formal nucleophilic halogenating reagents under mild reaction conditions.magnified image