A Novel Synthesis of 2-Functionalized Benzofurans by Palladium-Catalyzed Cycloisomerization of 2-(1-Hydroxyprop-2-ynyl)phenols Followed by Acid-Catalyzed Allylic Isomerization or Allylic Nucleophilic Substitution
作者:Bartolo Gabriele、Raffaella Mancuso、Giuseppe Salerno
DOI:10.1021/jo801444n
日期:2008.9.19
furans 3 and 2-alkoxymethylbenzofurans 4-6, based on palladium-catalyzed cycloisomerization of 2-(1-hydroxyprop-2-ynyl)phenols 1 under basic conditions to give 2-methylene-2,3-dihydrobenzofuran-3-ols 2, followed by acid-catalyzed isomerization or allylic nucleophilic substitution with alcohols as nucleophiles, is reported. Cycloisomerization reactions leading to 2 (80-98% yields) were carried out at
基于钯在碱性条件下催化2-(1-羟基丙-2-炔基)酚1的环异构化反应,生成2-羟甲基苯并呋喃3和2-烷氧基甲基苯并呋喃4-6。据报道,有3-二氢苯并呋喃-3-醇2,然后经酸催化的异构化或用醇作为亲核试剂进行烯丙基亲核取代。在碱的存在和催化量的PdX2 + 2KX(X = Cl,I)的存在下,在40℃下于甲醇中作为溶剂,进行导致2(80-98%收率)的环化反应。2的异构化反应很容易在25-60摄氏度的DME中作为溶剂,以H2SO4作为质子源,以65-90%的收率得到2-羟甲基苯并呋喃3。以类似的方式,