Honda Kiyoshi, Konishi Mari, Kawai Manabu, Yamada Akihisa, Takahashi Yasuhiko, Hoshino Yujiro, Inoue Seiichi
Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501, Japan.
Nat Prod Commun. 2012 Apr;7(4):459-62.
Optically active 1,3-bridged cyclobutanes 10 of the bicyclo[3.1.1]heptane ring system and 1,2-bridged cyclobutanes 11 of the bicyclo[3.2.0]heptane ring system were produced by UV irradiation of alpha,beta,gamma,delta-unsaturated esters 9a and 9c-f. The preference of endo-stereochemistry at C-6 bridged head was observed in cross-adducts 10. On the other hand, irradiation of conjugated dienol 9b led via only parallel cycloaddition to 1,2-bridged cyclobutane 11.
通过对α,β,γ,δ-不饱和酯9a和9c-f进行紫外线照射，生成了双环[3.1.1]庚烷环系的旋光性1,3-桥连环丁烷10和双环[3.2.0]庚烷环系的1,2-桥连环丁烷11。在交叉加合物10中观察到了C-6桥连端上内型立体化学的偏好。另一方面，共轭二烯醇9b的照射仅通过平行环加成生成1,2-桥连环丁烷11。
