Studies on synthesis of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene derivatives. IV. Photoreactions of 5-substituted-5H-dibenzo[a,d]cycloheptenes with 1,2-substituted olefins and the stereostructures of the cycloaddition products.
作者:Yasuhiro FUJIWARA、Motoshige SUMINO、Akira NOZAKI、Masao OKAMOTO
DOI:10.1248/cpb.37.1452
日期:——
The photoreactions of 5H-dibenzo[a, d]cyclohepten-5-one (la) and its 5-substituted derivatives (lz and ly) with olefins such as maleates, acrylates and crotonate gave the cycloaddition products (3a-e) in yields of 4-82%. Inversion reactions of the adducts (3b and 3c) with bases were carried out for the purpose of investigating the thermodynamic stability of the cycloadducts and the corresponding isomeric products (3b-t and 3c-f) were obtained. The stereostructures of the cycloaddition products and the isomeric products were determined by means of nuclear magnetic resonance (NMR) spectroscopy.
5H-二苯并[a,d]环庚烯-5-酮(1a)及其5-取代衍生物(1z和1y)与马来酸盐、丙烯酸盐和巴豆酸盐等烯烃的 photoreaction 产生环加成产物(3a-e),产率为4-82%。为了研究环加成产物的反应热力学稳定性,对这些加合物(3b和3c)进行了碱催化的转化反应,得到了相应的异构产物(3b-t和3c-f)。通过核磁共振(NMR)光谱法确定了环加成产物和异构产物的立体结构。