Enantioselective Intermolecular [2 + 2] Photocycloaddition Reactions of 2(1H)-Quinolones Induced by Visible Light Irradiation

详细信息    查看全文

• 作者：Andreas Tröster ; Rafael Alonso ; Andreas Bauer ; Thorsten Bach
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：June 29, 2016
• 年：2016
• 卷：138
• 期：25
• 页码：7808-7811
• 全文大小：366K
• 年卷期：0
• ISSN：1520-5126

文摘

In the presence of a chiral thioxanthone catalyst (10 mol %) the title compounds underwent a clean intermolecular [2 + 2] photocycloaddition with electron-deficient olefins at λ = 419 nm. The reactions not only proceeded with excellent regio- and diastereoselectivity but also delivered the respective cyclobutane products with significant enantiomeric excess (up to 95% ee). Key to the success of the reactions is a two-point hydrogen bonding between quinolone and catalyst enabling efficient energy transfer and high enantioface differentiation. Preliminary work indicated that solar irradiation can be used for this process and that the substrate scope can be further expanded to isoquinolones.