Etude des petits cycles—XXXVI. Photo-oxygenation d'alkylidenecyclopropanes. Syntheses specifiques d'alkenylcyclopropanols, de β′-hydroxy α-enones et d'α,α′-dienones
作者:G. Rousseau、P. le Perchec、J.M. Conia
DOI:10.1016/0040-4020(76)88022-2
日期:1976.1
The dye-sensitized photo-oxygenation of alkylidenecyclopropanes 1a–4a at –50°C gives the hydroperoxydes 1b–4b, which were reduced in situ by PPh3 into 1-alkenylcyclopropanols 1c–4c in high yield. At higher temperatures, 1b–4b rearranged exclusively into β′-hydroxy α-enones 1d–4d if pyridine was added (α,α′-dienones 1e–4e are also formed competitively in absence of pyridine). At 3°C the photosensitised
亚烷基环丙烷1a–4a在–50°C上的染料敏化光氧合产生了氢过氧化物1b–4b,它们被PPh 3原位还原成1-烯基环丙醇1c–4c,产率很高。在较高的温度下,如果添加吡啶,则1b–4b仅重排成β'-羟基α-烯酮1d–4d(在没有吡啶的情况下,竞争性地形成α,α'-二壬烯1e–4e)。在3°C时,亚烷基环丙烷1a–4a的光敏加氧会生成酮1k–4k,环丁酮1i–4i和β'-羟基α-烯酮1d–4d。讨论了产品的来源。