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.
Phosphine-Catalyzed (4 + 2) Cycloaddition of Conjugated Dienes with Enones and Its Asymmetric Variant
作者:Ke Li、Zhenjie Gan、Er-Qing Li、Zheng Duan
DOI:10.1021/acs.orglett.1c00780
日期:2021.4.16
reported a novel phosphine-catalyzed (4 + 2) cyclization reaction of electron-deficient conjugated dienes with enones to generate functionalized dihydropyran skeletons. A mechanistic investigation reveals that the reaction produces a new phosphonium zwitterion, which undergoes consecutive reactions. In addition, an asymmetric variant was developed by efficient and economical chiral phosphine catalysis.
Novel transformation of methylenecyclopropanes (MCPs) with acyl cyanoalkenes has been achieved to give oxaspiro[2.5]octenes. This annulation is successfully catalyzed by magnesium halides under mild reaction conditions, and shows a broad functional group tolerance. The reaction includes a rare reaction course, which involves an intramolecular oxa-Michael addition of Mg enolate after the ring opening
Synthesis of Quinoline and Quinolin-2(1H)-one Derivatives via Nickel Boride Promoted Reductive Cyclization
作者:Mrinal K. Bera、Rumpa Sarkar、Surya Kanta Samanta、Anila M. Menon、Deepak Chopra、Debabani Ganguly
DOI:10.1055/a-2116-5206
日期:2023.10
diversely substituted quinoline and quinolin-2-one derivatives is disclosed. In situ generated nickel boride proved to be an effective promoter of the reductive cyclization reaction. Broad substrate scope, mild reaction conditions, consistent yield, and a wide range of functional group tolerance are the other notable features of the newly discovered reaction. A large number of quinoline and quinolin-2-one