Regioselective Synthesis of Pyrone-Annulated Sulfur Heterocycles by Aryl Radical Cyclization
作者:K. Majumdar、S. Muhuri
DOI:10.1055/s-2006-942499
日期:2006.8
The tri-n-butyltin hydride mediated cyclization of a number of 4-(2′-bromophenoxymethyl)-7-methylthiopyrano[3,2-c]pyran-5-ones have been carried out to afford tetracyclic [6,6]pyranothiopyrans in 70-80% yield and good to excellent diastereoselectivity. The substrate ethers were obtained by a thio-Claisen rearrangement of the corresponding 4-(4′-aryloxybut-2′-ynyl)-6-methyl pyran-2-ones. The cis stereochemistry of the predominant diastereomer has been corroborated by single crystal X-ray analysis.
在三正丁基氢化锡介导下,对一些 4-(2′-溴苯氧甲基)-7-甲硫基吡喃并[3,2-c]吡喃-5-酮进行了环化反应,得到了四环[6,6]吡喃硫烷,产率为 70-80%,非对映选择性良好至极佳。底物醚是通过相应的 4-(4′-芳氧基丁-2′-炔基)-6-甲基吡喃-2-酮的硫代-克莱森重排反应得到的。单晶 X 射线分析证实了主要非对映异构体的顺式立体化学性质。