6 アリルアルコールの絶対構造決定のための円二色性アリルベンゾエート法 : 非縮退系における励起子相互作用

概要

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A new chiroptical method for determining the absolute configuration of allylic alcohols is described. The CD exciton chirality method can be extended to the system of allylic alcohol benzoates, nondegenerate systems composed of two different chromophores, i.e., benzoate with an allowed π→π^* transition at 230nm and C-C double bond with an allowed π→π^* transition around 195nm. Since these transitions are both polarized along the long axes of the chromophores, the exciton theory predicts that if the two long axes of benzoate and double bond chromophores constitute a positive exciton chirality, i.e., right-handed screwness, the first Cotton effect at longer wavelengths (230nm benzoate Cotton effect) is positive. On the other hand, if the allylic benzoate constitutes a left-handed screwness, the 230nm benzoate Cotton effect should be negative. The present method was confirmed by the CD spectra of a number of compounds. The absolute configuration of isoamijiol 34, a diterpene with dolastane skeleton isolated from a marine alga Dictyota linearis, was determined by application of this method. The present method has been also extended to acyclic allylic alcohols.
天然有機化合物討論会の論文
1982-09-10