Synthetic Photochemistry. LXIV. Mild Base-Induced<i>retro</i>-Benzilic-Acid Rearrangement of Isolated<i>proto</i>-Photocycloadducts of Methyl 2,4-Dioxopentanoate to Terpinolene. Facile Synthesis of<i>α</i>-Chamigrene and<i>α</i>-Chamigren-3-one
作者:Toshihide Hatsui、Jin-Jun Wang、Hitoshi Takeshita
DOI:10.1246/bcsj.67.2507
日期:1994.9
In the photoaddition reaction of terpinolene with methyl 2,4-dioxopentanoate, the products derived from the tetrasubstituted C=C were four proto-[2+2] photocycloadducts, together with ene reaction products. When these proto-cycloadducts were treated with aqueous sodium carbonate, a facile retro-benzilic acid rearrangement to form substituted cyclopentenone derivatives occurred. The product from the other trisubstituted C=C was an ordinary retro-aldol product of the [2+2] cycloadduct and an ene reaction product. One of the proto-photocycloadducts was transformed into α-chamigren-3-one and further to α-chamigrene.
在萜烯与甲基2,4-二氧戊酸酯的光加成反应中,来自四取代C=C的产物是四个原始的[2+2]光环加成物,以及烯反应产物。当这些原始环加成物与水合碳酸钠反应时,发生了易于进行的逆苯酸重排,形成取代的环戊烯酮衍生物。来自另一个三取代C=C的产物是普通的逆醛醇反应产物,源于[2+2]环加成物和烯反应产物。其中一个原始光环加成物转化为α-香茅烯-3-酮,进一步转化为α-香茅烯。