Strategies towards potent trypanocidal drugs: Application of Rh-catalyzed [2 + 2 + 2] cycloadditions, sulfonyl phthalide annulation and nitroalkene reactions for the synthesis of substituted quinones and their evaluation against Trypanosoma cruzi
作者:James M. Wood、Nishikant S. Satam、Renata G. Almeida、Vinicius S. Cristani、Dênis P. de Lima、Luiza Dantas-Pereira、Kelly Salomão、Rubem F.S. Menna-Barreto、Irishi N.N. Namboothiri、John F. Bower、Eufrânio N. da Silva Júnior
DOI:10.1016/j.bmc.2020.115565
日期:2020.8
Rhodium-catalyzed [2 + 2 + 2] cycloadditions, sulfonyl phthalideannulations and nitroalkene reactions have been employed for the synthesis of 56 quinone-based compounds. These were evaluated against Trypanosoma cruzi, the parasite that causes Chagas disease. The reactions described here are part of a program that aims to utilize modern, versatile and efficient synthetic methods for the one or two
An Improved Synthesis of 2-Nitrobenzo[<i>b</i>]furans
作者:Anne Tromelin、Pierre Demerseman、René Royer
DOI:10.1055/s-1985-31435
日期:——
2-Nitrobenzo[b]furans 4 are prepared in improved yields by reacting o-hydroxybenzaldehydes 1 and bromonitromethane (2) at low temperature in order to avoid the dehydration of the aldol intermediate 3 in the alkaline condensation medium. This aldol 3 is then quantitatively dehydrated by heating in acetic anhydride.
Palladium(0)-Catalyzed Dearomatization of 2-Nitrobenzofurans through Formal (3+2) Cycloadditions with Vinylcyclopropanes: A Straightforward Access to Cyclopenta[b]benzofurans
palladium-catalyzed dearomatization of electron-poor arenes, we report herein that various 2-nitrobenzofurans efficiently undergo a dearomative (3+2) cycloaddition with vinylcyclopropanes. This new method gives access to a wide variety of cyclopenta[b]benzofuran derivatives in a straightforward manner.
phosphine-catalyzed asymmetric dearomative [3+2] cycloaddition of 2-nitrobenzofurans with aldehyde-derived Morita–Baylis–Hillman (MBH) carbonates or allenoate was developed. The reaction with MBH carbonates resulted in a series of cyclopentabenzofurans containing three contiguous stereocenters with good to high yields, diastereoselectivities and enantioselectivities. The use of allenoate also gave the target product
Regio‐ and Stereoselective Cascade of β,γ‐Unsaturated Ketones by Dipeptided Phosphonium Salt Catalysis: Stereospecific Construction of Dihydrofuro‐Fused [2,3‐b] Skeletons
作者:Hongkui Zhang、Jiajia He、Yayun Chen、Cheng Zhuang、Chunhui Jiang、Kai Xiao、Zhishan Su、Xiaoyu Ren、Tianli Wang
DOI:10.1002/anie.202106046
日期:2021.9
heterocyclic molecules in high yields with excellent stereoselectivities. Moreover, mechanistic investigations revealed that the bifunctional phosphonium salt controlled the regio- and stereoselectivities of this cascade reaction, particularly proceeding through the initial ketone α-addition followed by O-participated substitution; and the multiple hydrogen-bonding interactions between Brønstedacid moieties