Copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins: A novel synthesis of furo[3,2-c]-coumarins
作者:Mingchuang He、Zhaohua Yan、Wangyang Wang、Fuyuan Zhu、Sen Lin
DOI:10.1016/j.tetlet.2018.09.007
日期:2018.10
A novel and efficient strategy for the synthesis of furo[3,2-c]coumarins has been developed via copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins. This redox-neutral reaction allows smooth and selective synthesis of 2-substituted, 3-substituted, 2,3-disubstituted and 2,3-fused polycyclic furo[3,2-c]coumarins.
通过铜催化酮肟肟酸酯与4-羟基香豆素的自由基/自由基交叉偶联,已经开发了一种新型有效的合成呋喃[3,2- c ]香豆素的策略。该氧化还原中性反应允许2-取代,3-取代,2,3-二取代和2,3-稠合的多环呋喃[3,2- c ]香豆素的平滑和选择性合成。
Iodine-mediated formal [3 + 2] annulation for synthesis of furocoumarin from oxime esters
作者:Quyen T. Pham、Phong Q. Le、Ha V. Dang、Hiep Q. Ha、Huong T. D. Nguyen、Thanh Truong、Tri Minh Le
DOI:10.1039/d0ra07566c
日期:——
A novel synthesis of furocoumarins was developed by a reaction between oxime esters and 4-hydroxycoumarins. The reaction was proposed to undergo radical mechanism mediated by iodine, a cheap and common laboratory reagent. Mechanistic studies showed the key for the successful transformation was the presence of α-iodoimine intermediate which facilitated the ring-closing step. The developed conditions
Metal-Free Synthesis of Furocoumarins: An Approach via Iodine-Promoted One-Pot Cyclization between 4-Hydroxycoumarins and Acetophenones
作者:Phuc H. Pham、Que T. D. Nguyen、Nhu K. Q. Tran、Vu H. H. Nguyen、Son. H. Doan、Hiep Q. Ha、Thanh Truong、Nam T. S. Phan
DOI:10.1002/ejoc.201800983
日期:2018.8.31
An iodine‐mediated one‐pot synthesis of furocoumarins has been developed. The furocoumarins were obtained in high yields in the presence of NH4OAc as an additive, whereas neither acidic nor basic additives were effective.
Abstract Facile synthesis of furo[3,2-c]coumarins (2a–g) via cyclocondensation of 4-hydroxycoumarin and α-tosyloxyketones (1a–g) is described. A plausible mechanism involving C-C bond formation followed by 5-exo-tet cyclization is suggested. GRAPHICAL ABSTRACT
A simple and efficient synthesis of furo[3,2-c]coumarin derivatives from 4-hydroxycoumarin and α-haloketones via a tandem O-alkylation/cyclisation protocol is described.
描述了一种通过串联O-烷基化/环化方案由4-羟基香豆素和α-卤代酮简单有效地合成呋喃[3,2- c ]香豆素衍生物的方法。