Organocatalytic Enantioselective Protonation for Photoreduction of Activated Ketones and Ketimines Induced by Visible Light. Issue 44 (4th October 2017)

• Record Type: Journal Article
• Authors: Lin, Lu; Bai, Xiangbin; Ye, Xinyi; Zhao, Xiaowei; Tan, Choon‐Hong; Jiang, Zhiyong
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 44(2017)
• Page Start: 13842
• Page End: 13846
• Publication Date: 2017-10-04
• Subjects: asymmetric photoredox catalysis -- cooperative catalysis -- organocatalysis -- photoreduction -- protonation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201707899
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The first catalytic asymmetric photoreduction of 1, 2‐diketones and α‐keto ketimines under visible light irradiation is reported. A transition‐metal‐free synergistic catalysis platform harnessing dicyanopyrazine‐derived chromophore (DPZ) as the photoredox catalyst and a non‐covalent chiral organocatalyst is effective for these transformations. With the flexible use of a chiral Brønsted acid or base in H + transfer interchange to control the elusive enantioselective protonation, a variety of chiral α‐hydroxy ketones and α‐amino ketones were obtained with high yields and enantioselectivities. Abstract : Enantioselective protonation : The first catalytic asymmetric photoreduction of 1, 2‐diketones and α‐keto ketimines under visible light irradiation relies on a transition‐metal‐free cooperative catalysis platform that harnesses dicyanopyrazine‐derived chromophore (DPZ) as the photoredox catalyst and a noncovalent chiral organocatalyst. A variety of chiral α‐hydroxy ketones and α‐amino ketones was obtained with high yields and enantioselectivities.