133379-93-8Relevant academic research and scientific papers
Catalyst-Free Synthesis of 2,3-Dihydrobenzofurans via a Formal [4+1] Annulation of Propargylamines with Sulfur Ylides
He, Xinwei,Xie, Mengqing,Tang, Qiang,Zuo, Youpeng,Li, Ruxue,Shang, Yongjia
, p. 11623 - 11638 (2019/10/02)
A simple, general route to the 2,3-dihydrobenzofurans substituted at C3 by an aryethynyl or aryl group, starting from propargylamine and its derivatives with benzoyl sulfonium salts, has been developed. This reaction involved an in situ generated o-quinone methide (o-QM) intermediate followed by [4+1] annulation with sulfur ylides. Notably, this protocol's features include moderate to excellent yields and remarkable diastereoselectivity (>20:1 dr in general), easy performance, as well as applicability to versatile 2,3-dihydrobenzofurans with aryethynyl or an aryl group via C-C and C-O bond formation in one pot without any catalyst in an aqueous mixed solvent.
Reaction of 3-Halogeno-2H-1-benzopyran-2-ones with Organometallic Compounds. Synthesis of 4-Alkyl-2H-1-benzopyran-2-ones. X-Ray Molecular Structure of 3-Bromo-3,4-dihydro-4-isopropylcoumarin
Alberola, Angel,Calvo, Blanca,Ortega, Alfonso Gonzalez,Vicente, Martina,Granda, Santiago G.,Van der Maelen, Juan F.
, p. 203 - 210 (2007/10/02)
3-Halogeno-2H-1-benzopyran-2-ones react with magnesium, lithium, aluminium and copper derivatives to give 3,4-dihydrocuomarins and 3-(o-hydroxyphenyl)propenols as major products.The nature and the ratio of the products in the final mixture depend on the solvent and on the organometallic reagent.Grignard derivatives yield 1,4-monoalkylation compounds in tetrahydrofuran (THF) or 1,2-dialkylation derivatives in toluene.In some cases the dehalogenation competes with the 1,2-alkylation process in the reactions with alkyllithiums.The presence of the halogen at C-3 increases the reductive ability of organoaluminiums.In general, the reaction with lithium dialkylcuprates leads to complex mixtures of products.The 4-alkyl-3-halogeno-3,4-dihydrocuomarins obtained undergo dehydrohalogenation easily, and lead to 4-alkylcuomarins in good yields.The tandem alkylation-dehydrohalogenation of 3-halogeno-2H-1-benzopyran-2-ones constitutes a versatile synthesis of 4-alkylcuomarins.
