Electrochemical Epoxidation and Carbon–Carbon Bond Cleavage for the Preparation of 3-Methyl-4-oxo-2-phenyl-4<i>H</i>-1-benzopyran-8-carboxylie Acid from 3-Methyl-2-phenyl-8-(1-propenyl)-4<i>H</i>-1-benzopyran-4-one
作者:Kenji Uneyama、Yosinori Masatsugu、Sigeru Torii
DOI:10.1246/bcsj.58.2361
日期:1985.8
Electrooxidative carbon–carbon bond cleavage is useful for the preparation of 3-methyl-4-oxo-2-phenyl-4H-1-benzopyran-8-carboxylic acid (1b) from 3-methyl-2-phenyl-8-(1-propenyl)-4H-1-benzopyran-4-one (2). Olefin 2 was transformed into 3-methyl-8-(1,2-epoxypropyl)-3-methyl-2-phenyl-4H-1-benzopyran-4-one (3) by the electrochemical bromohydrination in an MeCN–H2O–H2SO4–NaBr–(Pt) system followed by treatment
电氧化碳-碳键断裂可用于从 3-甲基-2-苯基-8-(1) 制备 3-甲基-4-氧代-2-苯基-4H-1-苯并吡喃-8-羧酸 (1b) -丙烯基)-4H-1-苯并吡喃-4-one (2)。烯烃 2 在 MeCN-H2O-H2SO4 中通过电化学溴氢化反应转化为 3-methyl-8-(1,2-epoxypropyl)-3-methyl-2-phenyl-4H-1-benzopyran-4-one (3) –NaBr–(Pt) 系统,然后处理氢氧化钠水溶液 (94%)。环氧化物 3 在 MeOH-H2SO4-(C) 系统中被电氧化,以 83% 的产率得到 8-formyl-3-methyl-2-phenyl-4H-1-benzopyran-4-one (4)。4 在回流的 2-丁酮中过氧化氢氧化得到 1b,产率为 86%。