An Investigation of the Yang Photocyclization Reaction in the Solid State: Asymmetric Induction Studies and Crystal Structure−Reactivity Relationships
作者:Mordechai Leibovitch、Gunnar Olovsson、John R. Scheffer、James Trotter
DOI:10.1021/ja9823013
日期:1998.12.1
investigated in the solid state and solution. In both media, ketones bearing methyl substituents α to the benzoyl group undergo stereoselective Yang photocyclization to afford endo-arylcyclobutanols. Quantum yield and quenching studies in solution show that the reactions are efficient triplet-mediated processes. Asymmetric induction studies were carried out by providing the reactants with carboxylic acid
已在固态和溶液中研究了具有基本顺-4-叔丁基-1-苯甲酰基环己烷或 2-苯甲酰基金刚烷结构的 16 种酮的 Norrish/Yang II 型光化学。在这两种介质中,带有甲基取代基α到苯甲酰基的酮经历立体选择性阳光环化以提供内芳基环丁醇。溶液中的量子产率和猝灭研究表明,这些反应是有效的三重态介导过程。不对称诱导研究是通过为反应物提供羧酸取代基来进行的,“离子手性助剂”通过与旋光胺形成盐而连接到这些羧酸取代基上。溶液中的盐(总共 17 种)的辐照得到外消旋环丁醇,但在结晶状态下,获得了中等至接近定量的对映体过量。对 10 种中性酮和四种盐成功进行了单晶 X 射线衍射研究。这允许识别反应性γ-氢原子并...