Though numerous cyanation reactions have been developed for the synthesis of benzonitriles, the construction of valuable fully substituted benzonitriles is still a challenging task. Herein, we reported a tertiary amine-catalyzed [3 + 3]-benzannulation for the green synthesis of CF3-functionalized fully substituted benzonitriles. This strategy features exclusive chemoselectivity, high atom-economy,
Organocatalytic Asymmetric [4+2] Cycloaddition of 1-Acetylcyclopentene and 1-Acetylcyclohexene for the Synthesis of Fused Carbocycles
作者:Utpal Nath、Subhas Chandra Pan
DOI:10.1002/ejoc.201701238
日期:2017.11.24
The first organocatalytic asymmetric [4+2] cycloaddition reaction employing 1-acetylcyclopentene and 1-acetylcyclohexene is described. Enones having cyano group are used as the dienophile partner in this method. The reaction provides a useful practical route for the synthesis of bicyclic fused carbocycles having four contiguous stereocentres.
Synthesis Route to Pyrrolones from α-Cyano α,β-Unsaturated Ketones and α-Isocyano Esters by Oxidative Dearomatization of 2-Aminofuran Intermediates
作者:Anil K. Mahida、Someshwar B. Kale、Utpal Das
DOI:10.1002/ejoc.201701194
日期:2017.11.24
A straightforward catalyst-free, ligand-free, and metal-free synthesis of 2-aminofurans through [4+1] cycloaddition of isocyanoacetates and electron-deficient alkenes is developed. The products are obtained in high yields without any column chromatography. Oxidative dearomatization of the furan products leads to pyrrolones in high yields.
domino process from Morita-Baylis-Hillman carbonates of isatins and acrylate and [small alpha]-cyano-[small alpha],[small beta]-unsaturated ketones to deliver highly enantioenriched tetrahydrofuro[2',3':4,5]pyrano[2,3-b]indoles was disclosed catalysed by cinchona-derived tertiary amines, involving [small alpha]-regioselective cyclopropanation, ring-opening,...
A rare intermolecular annulation of donor–acceptor cyclopropanes with alkenes has been developed by using a methylenecyclopropane (MCP) and acyl cyanoalkenes to give dihydrofurans or furans. The dihydrofurans were synthesized in the presence of a catalytic amount of the base and were readily converted to the furans by using a stoichiometric amount of the base. A 1H NMR study revealed that the ring-opened
通过使用亚甲基环丙烷(MCP)和酰基氰基烯烃,开发了一种罕见的供体-受体环丙烷与烯烃的分子间环化反应,得到二氢呋喃或呋喃。二氢呋喃是在催化量的碱存在下合成的,并且通过使用化学计量量的碱很容易转化为呋喃。 1 H NMR 研究表明,开环的 MCP 与烯烃发生反应。