Gold(I)-Catalyzed Formal Intramolecular Dehydro-Diels–Alder Reaction of Ynamide-ynes: Synthesis of Functionalized Benzo[<i>b</i>]carbazoles
作者:Wei Xu、Gaonan Wang、Xin Xie、Yuanhong Liu
DOI:10.1021/acs.orglett.8b01145
日期:2018.6.1
ynamide-ynes via a formal dehydro-Diels–Alder reaction has been developed, providing an attractive route to diversely substituted benzo[b]carbazoles. The reaction likely proceeds via regioselective attack of the pendant alkyne moiety to a keteniminium ion intermediate followed by benzannulation. The method offers several advantages such as high efficiency, mild reaction conditions, and wide functional group
已经开发了通过正式的脱氢-狄尔斯-阿尔德反应的金催化的炔基-炔烃环异构化反应,为各种取代的苯并[ b ]咔唑提供了诱人的途径。该反应可能是通过炔烃侧基区域选择性地攻击酮亚胺离子中间体并随后进行苯环化而进行的。该方法具有许多优点,例如高效,温和的反应条件和宽泛的官能团耐受性,可作为对乙酰胺炔炔的热DDA反应的高度有用的补充。
Intermolecular Gold-Catalyzed Cycloaddition of Alkynes with Oxoalkenes
作者:Carla Obradors、Antonio M. Echavarren
DOI:10.1002/chem.201300131
日期:2013.3.11
As good as gold: Gold(I) catalyzes a new intermolecular reaction of terminal alkynes with functionalized alkenes that gives 8‐oxabicyclo[3.2.1]oct‐3‐enes by a [2+2+2] cycloaddition process in which two CC bonds and one CO bond are formed (see scheme).
Gold-Catalyzed Formal [3 + 2] Cycloaddition of Ynamides with 4,5-Dihydro-1,2,4-oxadiazoles: Synthesis of Functionalized 4-Aminoimidazoles
作者:Wei Xu、Gaonan Wang、Ning Sun、Yuanhong Liu
DOI:10.1021/acs.orglett.7b01469
日期:2017.6.16
A gold-catalyzed formal [3 + 2] cycloaddition of ynamides with 4,5-dihydro-1,2,4-oxadiazoles has been developed. The reaction provides a concise and regioselective access to highly functionalized 4-aminoimidazoles likely via the formation of an α-imino gold carbene intermediate followed by cyclization. 4,5-Dihydro-1,2,4-oxadiazole was found to act as an efficient N-iminonitrene equivalent in these
A ligand‐directed divergent scaffold synthesis was explored by varying the ligands for the gold(I) catalysts and the nucleophiles in the cycloisomerization reactions of oxindole based 1,6‐enynes. The strategy afforded several distinct and structurally complex molecular scaffolds.
Benzofurazan <i>N</i>-Oxides as Mild Reagents for the Generation of α-Imino Gold Carbenes: Synthesis of Functionalized 7-Nitroindoles
作者:Wei Xu、Yulong Chen、Ali Wang、Yuanhong Liu
DOI:10.1021/acs.orglett.9b02893
日期:2019.9.20
An efficient gold-catalyzed [3 + 2] annulation of benzofurazan N-oxides with ynamides has been developed, which provides a concise and regioselective access to highly functionalized 7-nitroindoles. Although N-oxides are often considered as oxygentransfer reagents in gold catalysis, benzofurazan N-oxide was found to act as a facile precursor for an α-imino gold carbene intermediate. Benzofurazan can