for the preparation of 3-substituted isocoumarins via palladium-catalyzed nucleophilic addition/oxidative annulation of bromoalkynes with benzoic acids has been developed. Remarkably, preliminary mechanistic studies indicated that the transformation might proceed via a stereo- and regioselective nucleophilic addition and C–H functionalization procedure.
The Rh(III)-catalyzed C–H activation initiated cyclization of benzoicacids with electron-rich geminal-substituted vinyl acetates was described. The reaction was employed to prepare a range of 3-aryl and 3-alkyl substituted isocoumarins selectively.
Sulfoxonium Ylides as Carbene Precursors: Rhodium(III)‐Catalyzed Sequential C−H Functionalization, Selective Enol Oxygen‐Atom Nucleophilic Addition, and Hydrolysis
作者:Yuanqiong Huang、Xueli Lyu、Hongjian Song、Qingmin Wang
DOI:10.1002/adsc.201900861
日期:2019.11.19
Herein, we report a protocol for Rh(III)‐catalyzed annulation reactions between oxazolines and sulfoxonium ylides via a sequence involving C−H activation, selective enol oxygen‐atom nucleophilic addition, and hydrolysis. This practical, operationally simple protocol has a wide substrate range, excellent regioselectivity, and moderate to good yields.
Rhodium(<scp>iii</scp>)-catalyzed chemodivergent annulations between <i>N</i>-methoxybenzamides and sulfoxonium ylides <i>via</i> C–H activation
作者:Youwei Xu、Guangfan Zheng、Xifa Yang、Xingwei Li
DOI:10.1039/c7cc07753j
日期:——
Chemodivergent and redox-neutral annulations between N-methoxybenzamides and sulfoxonium ylides have been realized via Rh(III)-catalyzed C–H activation. The sulfoxonium ylide acts as a carbene precursor, and coupling occurs under acid-controlled conditions, where Zn(OTf)2 and PivOH promote chemodivergent cyclizations.
Synthesis of Isocoumarin Derivatives via the Copper-Catalyzed Tandem Sequential Cyclization of 2- Halo-<i>N</i>-phenyl Benzamides and Acyclic 1,3-Diketones
作者:Veerababurao Kavala、Cheng-Chuan Wang、Deepak Kumar Barange、Chun-Wei Kuo、Po-Min Lei、Ching-Fa Yao
DOI:10.1021/jo300501j
日期:2012.6.1
A facile and rapid synthesis of isocoumarin derivatives using a copper-catalyzed tandem C–C/C–O coupling strategy from readily available substrates is described. The reactions of a wide range of 2-iodo-N-phenyl benzamides and acyclic diketones as starting materials were investigated.