Unexpected and efficient photochemical rearrangement of 6-hydroxyethylpyran-2-ones to 4-AIkylidene-5,6-dihydropyrans
作者:Charles E. Chase、Michael B. Jarstfer、Atta M. Arif、F.G. West
DOI:10.1016/0040-4039(95)01828-6
日期:1995.11
pendant alcohols underwent conversion to dihydropyrans 7 via irradiation in MeOH followed by stirring in the presence of catalytic HCl. This process requires the intervention of a prior skeletal rearrangement of the starting pyran-2-ones to place the hydroxyalkyl substituent at C-4, along with temporary incorporation of MeOH. Homologous substrates 2f–g underwent intramolecular 1,6-addition exclusively
通过在MeOH中辐照,然后在有催化HCl的情况下进行搅拌,使带有Pyran-2-ones 2a-e的侧链醇转化为二氢吡喃7。此过程需要干预先进行吡喃-2-酮的骨架重排,以将羟烷基取代基置于C-4处,以及暂时掺入MeOH。同源底物2f-g仅进行分子内1,6-加成,以提供高产率的螺内酯9。