Unexpected regioselectivity in the photocyclization of a chiral 2,3-bisbenzylidenesuccinate, leading to a podophyllotoxin related cyclolignan
作者:Kamil Lisiecki、Piotr Roszkowski、Krzysztof K. Krawczyk、Jan. K. Maurin、Zbigniew Czarnocki
DOI:10.1016/j.jphotochem.2018.06.023
日期:2018.9
transition states of this reaction. Introducing L-prolinol as a chiral auxiliary, macrolactonization and subsequent photocyclization of the atropoisomeric cyclic amide ester led to new cyclolignan analogue. By comparing the regioselectivity observed in this study with our previous results, some general rules regarding the photocyclization of chiral 2,3-bisbenzylidenesuccinates could be established.
3′,4′,5′-三甲氧基苯乙酮与衍生自胡椒醛的亚苄基琥珀酸酯之间的Stobbe缩合得到唯一的产物Z,E -2,3-双亚苄基琥珀酸酯。通过考虑该反应的过渡态的纽曼投影来解释这种区域选择性。引入L-脯氨醇作为手性助剂,阻转异构体环状酰胺酯的大内酯化和随后的光环化导致了新的cyclolignan类似物。通过将本研究中观察到的区域选择性与我们先前的结果进行比较,可以建立一些有关手性2,3-双亚苄基琥珀酸酯的光环化的一般规则。