A Lewis acid-promoted cyclization of ethenetricarboxylate derivative aromatic compounds. Novel syntheses of oxindoles and benzofuranones via Friedel–Crafts intramolecular Michael addition
作者:Shoko Yamazaki、Satoshi Morikawa、Yuko Iwata、Machiko Yamamoto、Kaori Kuramoto
DOI:10.1039/b408728c
日期:——
A novel cyclization reaction of ethenetricarboxylate derivative aromatic compounds in the presence of various Lewis acids gave benzo-annulated cyclic compounds such as oxindole and benzofuran derivatives via Friedel-Crafts intramolecular Michael addition in high yields. For example, the reaction of diethyl 2-[(N-methyl-N-phenylcarbamoyl)methylene]malonate (1a) in the presence of ZnCl2 at room temperature
在各种路易斯酸的存在下,乙烯三羧酸酯衍生物芳族化合物的新型环化反应可通过弗里德-克来福特分子内迈克尔加成反应以高收率得到苯并环化的环状化合物,例如羟吲哚和苯并呋喃衍生物。例如,在室温下在ZnCl 2存在下使2-[((N-甲基-N-苯基氨基甲酰基)亚甲基]丙二酸二乙酯(1a)在室温下反应,得到2-(1-甲基-2-氧代吲哚-3-基)二乙基酯。丙二酸酯(2a),产率98%。反应还用催化量的路易斯酸例如AlCl 3,ZnCl 2,ZnBr 2,Sc(OTf)3或InBr 3进行。