Readily Removable Directing Group Assisted Chemo- and Regioselective C(sp<sup>3</sup>)H Activation by Palladium Catalysis
作者:Yun-Fei Zhang、Hong-Wei Zhao、Hui Wang、Jiang-Bo Wei、Zhang-Jie Shi
DOI:10.1002/anie.201505932
日期:2015.11.9
Currently used directing groups for selective aliphatic β‐functionalization of carbonyl compounds show excellent reactivity and selectivity with an amide as a linker. Described herein is 2‐piconimide, used for the first time with commercially available 2‐picolinamide/2‐picolic acid as precursors, to directCH arylation/alkenylation by palladium catalysis. The directing group is essential for promoting
Nickel-Catalyzed Aminoxylation of Inert Aliphatic C(sp<sup>3</sup>)–H Bonds with Stable Nitroxyl Radicals under Air: One-Pot Route to α-Formyl Acid Derivatives
作者:Chunxia Wang、Luoqiang Zhang、Jingsong You
DOI:10.1021/acs.orglett.7b00479
日期:2017.4.7
Nickel-catalyzed aminoxylation of an unactivated C(sp3)–H bond with a stable nitroxyl radical has been accomplished for the first time to offer various N-alkoxyamine derivatives, which further enables a one-pot approach to α-formyl acid derivatives. The aminoxylation process reported also provides direct evidence for the oxidative addition of a cyclometallic intermediate with a free radical, which
Nickel-Catalyzed Site-Selective Alkylation of Unactivated C(sp<sup>3</sup>)–H Bonds
作者:Xuesong Wu、Yan Zhao、Haibo Ge
DOI:10.1021/ja413131m
日期:2014.2.5
The direct alkylation of unactivated sp(3) C-H bonds of aliphatic amides was achieved via nickel catalysis with the assist of a bidentate directing group. The reaction favors the C-H bonds of methyl groups over the methylene C-H bonds and tolerates various functional groups. Moreover, this reaction shows a predominant preference for sp(3) C-H bonds of methyl groups via a five-membered ring intermediate
Synthesis of N–H-Free 1,4-Dihydroisoquinoline-3(2<i>H</i>)-ones via Pd-Catalyzed C–H Olefination Using Polyfluorosulfinyl as the Auxiliary Group
作者:Yu-Hao Chen、Nan-Qi Shao、Chen Li、Dong-Hui Wang
DOI:10.1021/acs.orglett.0c01979
日期:2020.8.7
Pd(II)-catalyzed olefination of aryl C–H bonds with a self-cleaving 2-chlorotretafluoroethylsulfinyl (−SOCF2CF2Cl) auxiliary was developed. In the reaction mixture, the olefination products underwent in situ Michael addition and the subsequent expulsion of the auxiliary to provide the N–H-free 1,4-dihydroisoquinoline-3(2H)-one products. Mechanistic studies reveal that the auxiliary group is crucial for C–H activation
开发了具有自裂解2-氯四氟乙基亚磺酰基(-SOCF 2 CF 2 Cl)助剂的Pd(II)催化的芳基CH键的烯化。在反应混合物中,将烯烃化产物进行原位迈克尔加成反应,随后将助剂逐出,以提供不含NH的1,4-二氢异喹啉-3(2 H)-一产物。机理研究表明,辅助基团对于C–H活化至关重要,并且Na 2 CO 3和一种醇溶剂在促进多氟烷基亚磺酰基辅助剂的裂解中起关键作用。