Visible‐Light‐Induced Oxidative α‐Alkylation of Glycine Derivatives with Ethers under Metal‐Free Conditions

• Published in: European journal of organic chemistry 2021-11, Vol.2021 (44), p.5914-5921
• Main Authors: Song, Yang, Zhang, Hao, Guo, Jiabao, Shao, Yifei, Ding, Yuzhou, Zhu, Li, Yao, Xiaoquan
• Format: Article
• Language: English
• Subjects: Alkylation; Ambient temperature; Amides; Butyl hydroperoxide; C−H activation; Eosin Y; Esters; Ethers; Functional groups; Glycine; Glycine derivatives; Ketones; Oxidizing agents; Photocatalysis
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202101242

In this work, a visible‐light‐induced oxidative α‐alkylation of glycine derivatives with ethers has been developed in the presence of catalytic Eosin Y. Under the blue light of a 3 W LED, a range of α‐etherized glycine derivatives, including α‐amino esters, α‐amino ketones and α‐amino amides, were achieved with good to excellent yields and functional group tolerance with tert‐butyl hydroperoxide (TBHP) as oxidant at ambient temperature. The operationally easy procedure provides an economical, metal‐free, and mild alternative for the synthesis of the α‐etherized glycine derivatives. A novel visible‐light‐induced coupling reaction of glycine derivatives with ethers is reported. Its scope was expanded to α‐amino esters,α‐amino ketones and α‐amino amides. Not only various α‐amino esters but also cyclic and acyclic ethers were well tolerated in this strategy. Metal‐free catalysis and efficient synthesis under mild conditions are notable features of this method.