Formation and Disproportionation of Xanthenols to Xanthenes and Xanthones and Their Use in Synthesis
作者:Zeyu Shi、Si Chen、Qiong Xiao、Dali Yin
DOI:10.1021/acs.joc.0c02694
日期:2021.2.19
A facile and versatile strategy employing TiCl4-mediated cyclization followed by a Cannizzaro reaction has been developed for the synthesis of various xanthene derivatives. The reaction proceeded smoothly to afford both xanthenes/xanthones or their sulfur derivatives and tolerated a wide range of electronically diverse substrates. Using this methodology, pranoprofen was synthesized in three steps in
Catalytic cyanation of aryl iodides using DMF and ammonium bicarbonate as the combined source of cyanide: a dual role of copper catalysts
作者:Amit B. Pawar、Sukbok Chang
DOI:10.1039/c3cc47926a
日期:——
Cu(II)-catalyzed cyanation of aryliodides has been developed using DMF and ammonium bicarbonate as the combined source of cyanide. It is assumed that copper is involved both in the generation of "CN" units from DMF-ammonia and in the cyanation of aryl halides. A range of electron-rich and fused (hetero)aryliodides underwent cyanation resulting in moderate to good yields.
Metal-Free Oxidative Coupling: Xanthone Formation<i>via</i>Direct Annulation of 2-Aryloxybenzaldehyde using Tetrabutylammonium Bromide as a Promoter in Aqueous Medium
作者:Honghua Rao、Xinyi Ma、Qianzi Liu、Zhongfeng Li、Shengli Cao、Chao-Jun Li
DOI:10.1002/adsc.201300488
日期:2013.8.12
AbstractA metal‐free intramolecular annulation of 2‐aryloxybenzaldehydes to xanthones is disclosed, which proceeds through the direct oxidative coupling of an aldehyde CH bond and aromatic CH bonds using tetrabutylammonium bromide (TBAB) as a promoter in aqueous medium. This strategy works smoothly in the presence of both electron‐donating and electron‐withdrawing groups, and displays good tolerance towards catalytically reactive substituents, thus promising further functionalizations of xanthone products.magnified image
Rhodium-Catalyzed Xanthone Formation from 2-Aryloxybenzaldehydes via Cross-Dehydrogenative Coupling (CDC)
作者:Ping Wang、Honghua Rao、Ruimao Hua、Chao-Jun Li
DOI:10.1021/ol203381q
日期:2012.2.3
A concise and straightforward strategy to construct a xanthone skeleton via an intramolecular cross-dehydrogenative coupling (CDC) of 2-aryloxybenzaldehydes has been developed. The reaction proceeded smoothly without any need of preactivation of the aldehyde group. It can tolerate various functional groups and provides an applicable protocol to construct a wide range of xanthone derivatives.
Synthesis of Xanthones via Copper(II)-Catalyzed Dehydrogenative Cyclization and Successive Aromatization in a One-Step Sequence
作者:Yoon Hu Jang、Yo-Sep Yang、Seung Hwan Son、Hyung-Seok Yoo、Jeong-Won Shin、Hyuck-Jae Won、Soo Lim Kim、Changjin Lim、Nam-Jung Kim