Synthesis of 2(3H)-benzofuranone derivatives by copper (i)-promoted substitution reactions of active methylene carbanions
作者:Jun-ichiro Setsune、Takashi Ueda、Katsumi Shikata、Kimihiro Matsukawa、Toshiya Iida、Teijiro Kitao
DOI:10.1016/s0040-4020(01)90550-2
日期:——
carbanions by copper(I) in the sub-stitution reaction toward aryl halides and allyl halides was demonstrated. Derivatives of 2(3H)-benzofuranones (2, 14 -18) were prepared in a one-pot procedure by the reaction of copper(I) diethyl malonate with sodium o-bromophenoxide. 2-Hydroxybenzofuran (4) and its 2-amino derivative (5) were obtained by using copper(I) salts of ethyl acetoacetate and ethyl cyanoacetate
证实了在取代反应中,铜(I)对芳基卤化物和烯丙基卤化物活化了软质碳负离子。通过一锅法通过丙二酸铜(I)丙二酸铜(I)与邻溴代苯甲酸钠的反应制备2(3H)-苯并呋喃酮(2,14 -18)的衍生物。通过使用乙酰乙酸乙酯和氰基乙酸乙酯的铜(I)盐获得2-羟基苯并呋喃(4)及其2-氨基衍生物(5)。对溴苯甲酸钠与丙二酸铜(I)的反应生成对-1,1,2,2-四乙氧基乙氧基乙基酚(7,8)。在酸性条件下,将3-羧乙氧基-3-β-甲基烯丙基-2-苯并呋喃酮(14)转化为螺[2-苯并呋喃酮-3,3'-(5',5'-二甲基)-γ-丁内酯](22) 。后者化合物进一步脱羧得到螺[2-苯并呋喃酮-3,1'-(2',2'