本文研究了青蒿素降解产物失碳倍半萜内酯(Ⅰ)的旋光谱和圆二色谱,推断了它的绝对构型。并用旋光谱和圆二色谱研究了(Ⅰ)的最终氧化产物(Ⅲ)和还原产物(Ⅳ)的立体化学及青蒿乙素的氢化产物(Ⅴ)的立体化学。根据这些结果并结合化学反应论证了(Ⅰ)的绝对构型。 In this paper, the spin spectrum and circular dichroism of the lost carbon sesquiterpenoid lactone (Ⅰ) of artemisinin degradation product were studied, and its absolute configuration was deduced. The stereochemistry of the final oxidation product (Ⅲ) and the reduction product (Ⅳ) of (Ⅰ) and the stereochemistry of the hydrogenation product (Ⅴ) of artemethyleneimine were studied by means of spinodal and circular dichroism. Based on these results and combined with chemical reaction, the absolute configuration of (Ⅰ) is demonstrated.