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.
Modular access to furo[3,2-c]chromen-4-ones via Yb(OTf)3-catalyzed [3 + 2] annulation of 4-hydroxycoumarins with β-nitroalkenes
作者:Hua Wang、Qin Ma、Yifei Xu、Yanyan Sun、Siyuan Zhao、Shaoyin Wang、Xinwei He
DOI:10.1039/d4ra03962a
日期:——
A facile and efficient strategy for modular access to furo[3,2-c]chromen-4-ones using 4-hydroxycoumarin and β-nitroalkenes via Lewis acid-catalyzed formal [3 + 2] annulation protocol is described. This reaction proceeds via cascade Michaeladdition/nucleophilic addition/elimination in the presence of Yb(OTf)3, which involves the formation of two new σ (C-C and C-O) bonds for the construction of a novel
(2-chloro-2-nitroethenyl)benzenes as synthons: a general method for the preparation of 2,3-dihydro- 2-nitro-3-phenyl-4H-furo [3,2-c] [1]benzopyran-4-ones and 3-phenyl-4H-furo[3,2-c][1]benzopyran-4-ones