The stereoselective thermal rearrangement of chiral lophine peroxides
作者:Masaru Kimura、Gonghao Lu、Hiroshi Iga、Mitsuru Tsunenaga、Zhiqiang Zhang、Zhizhi Hu
DOI:10.1016/j.tetlet.2007.01.146
日期:2007.4
The thermal reaction of chiral 2-phenyl-4-(p-X-phenyl)-5-(p-Y-phenyl)-4-tert-butyldimethylsilylperoxy-4H-isoimidazoles (5b: X = CF3, Y = OMe; 5c: X = CF3, Y = F) was carried out in DMSO. The chiral 2-phenyl-5-(p-X-phenyl)-5-(p-Y-phenyl)-5H-imidazol-4-ones (4b: X = CF3, Y = OMe; 4c: X = CF3, Y = F) were quantitatively obtained in 50–60% enantiomer excess (ee). The mechanism for the reaction was proved
imidazolones in high yields, instead of amidines with chemiluminescence (CL). The corresponding imidazolols were believed to intermediates and they were successfully obtained by treating the peroxides with DMSO without the base. The diminished CL was because of the reduction of the hydroperoxides with DMSO. The imidazolols subsequently underwent smooth base‐mediated rearrangement to afford imidazolones