Studies in Sigmatropic Rearrangement: Synthesis of a [6,6]Pyranothiopyran Ring System by Sequential Claisen Rearrangement and Pyridine Hydrotribromide Mediated Regioselective “6-Endo” Cyclization
作者:K. C. Majumdar、U. K. Kundu、S. K. Ghosh
DOI:10.1021/ol020088g
日期:2002.8.1
afford 4-aryloxymethylthiopyrano[3,2-c][1]benzopyran-5(2H)-ones which are subsequently subjected to heating in o-dichlorobenzene in the presence of N,N-diethylaniline and then treated with pyridine hydrotribromide to give [6,6]pyranothiopyrans in almost quantitative yield.
[反应:参见文章] 4-(4'-Aryloxybut-2'-ynylthio)[1]苯并吡喃-2-酮在氯苯中回流,得到4-芳氧基甲硫基吡喃并[3,2-c] [1]苯并吡喃-5( 2H)-酮,随后在N,N-二乙基苯胺存在下在邻二氯苯中加热,然后用氢溴酸吡啶处理,以几乎定量的产率得到[6,6]吡喃硫吡喃。