A New [2+2+1] Heterocyclization for the Synthesis of 2,3,5-Trisubstituted Thiophenes under Microwave Irradiation
作者:Bo Jiang、Shu-Jiang Tu、Hai-Wei Xu、Guan-Hua Ma
DOI:10.1055/s-0033-1339917
日期:——
Abstract A new three-component strategy for the efficient synthesis of 2,3,5-trisubstituted thiophene derivatives through a [2+2+1] heterocyclization between 3-(2-aryl-2-oxoethylidene)-2-oxindoles and α-thiocyanato ketones under microwave irradiation is described. The bond-forming efficiency, accessibility, and generality of this synthesis make it highly valuable to assemble thiophene scaffolds. A new three-component
development of a rapid, highly efficient, and one-pot synthesis of C3-α-prenylated oxindoles with simple reagents is described. The process is based on zinc-mediated α-regioselective prenylation of 3-acylidene-oxindole with commercially available prenyl bromide using inexpensive CeCl3 as the catalyst. The new transformation tolerates a wide range of 3-acylidene-oxindoles, providing easy access to a variety
Dimerization of 3-(2-aryl-2-oxoethylidene)oxindoles
作者:B. V. Paponov、O. V. Shishkin、S. V. Shishkina、R. I. Zubatyuk、A. L. Kalyuzhny、V. I. Musatov
DOI:10.1007/s11172-008-0098-4
日期:2008.3
Abstract6-Aroyl-7-arylindolo[3,4-jk]phenanthridin-5(4H)-ones (2a–i) were synthesized by heating 3-(2-aryl-2-oxoethylidene)-2,3-dihydroindol-2-ones (1a–i) in DMF. Compounds 2a–i are formed via the dimerization of two molecules of unsaturated ketones 1a–i proceeding as the [2+4] cycloaddition through the formation of intermediate spiro adducts. The further Pfitzinger rearrangement, decarboxylation, and heteroaromatization
A formal [1 + 2 + 3] annulation of methyleneindolinones with o-alkenyl arylisocyanides has been developed for the general and efficient synthesis of both symmetrical and unsymmetrical indolo[3,2-b]carbazoles. The chemoselectivity of this domino reaction was tuned by a tethered alkenyl group, which enables successive formation of three new bonds and two rings from readily accessible starting materials
已开发了一种亚甲基吲哚酮与邻链烯基芳基异氰酸酯的正式[1 + 2 + 3]环合结构,用于对称和不对称的吲哚[3,2- b ]咔唑的常规合成。该多米诺反应的化学选择性通过束缚链烯基进行调节,该链烯基能够在一次操作中由易于接近的起始原料连续形成三个新键和两个环。此外,该方法被用作生物碱麦拉西唑C合成中的关键步骤。
Highly diastereoselective synthesis of spiro[cyclopropane-1,3′-indolin]-2′-ones via catalyst-free cyclopropanation using ethyl diazoacetate
作者:Ram Awatar Maurya、Chada Narsimha Reddy、Geeta Sai Mani、Jeevak Sopanrao Kapure、Praveen Reddy Adiyala、Jagadeesh Babu Nanubolu、Kiran Kumar Singarapu、Ahmed Kamal
DOI:10.1016/j.tet.2014.05.065
日期:2014.8
Substituted 3-methyleneindolin-2-ones were efficiently cyclopropanated with ethyl diazoacetate to yield spiro[cyclopropane-1,3'-indolin]-2'-ones in a catalyst-free and highly diastereoselective reaction in a mixture of ethanol acetonitrile (1:1 v/v) as solvent. (C) 2014 Elsevier Ltd. All rights reserved.