Photoinduced decarboxylative borylation of carboxylic acids
作者:Alexander Fawcett、Johan Pradeilles、Yahui Wang、Tatsuya Mutsuga、Eddie L. Myers、Varinder K. Aggarwal
DOI:10.1126/science.aan3679
日期:2017.7.21
283 Light facilitates the replacement of carboxylic acids with boron esters in the absence of metal catalysts. The conversion of widely available carboxylic acids into versatile boronic esters would be highly enabling for synthesis. We found that this transformation can be effected by illuminating the N-hydroxyphthalimide ester derivative of the carboxylic acid under visible light at room temperature
Organocatalyzed, Visible-Light Photoredox-Mediated, One-Pot Minisci Reaction Using Carboxylic Acids via <i>N</i>-(Acyloxy)phthalimides
作者:Trevor C. Sherwood、Ning Li、Aliza N. Yazdani、T. G. Murali Dhar
DOI:10.1021/acs.joc.8b00205
日期:2018.3.2
one-pot Minisci reaction has been developed using visible light, an organic photocatalyst, and carboxylic acids as radical precursors via the intermediacy of in situ-generated N-(acyloxy)phthalimides. The conditions employed are mild, demonstrate a high degree of functional group tolerance, and do not require a large excess of the carboxylic acid reactant. As a result, this reaction can be applied to
A Visible Light-Driven Minisci-Type Reaction with N-Hydroxyphthalimide Esters
作者:Lisa Kammer、Aliyaah Rahman、Till Opatz
DOI:10.3390/molecules23040764
日期:——
A visible light-promoted protocol for the redox-neutral coupling of N-hydroxyphthalimide esters with different N-heterocyclic compounds is described. The reaction proceeds through an alkyl radical intermediate generated by reductive decarboxylation of N-hydroxyphthalimide esters. In contrast to the original Minisci protocol, polyalkylation can largely be avoided. Mechanistic investigations revealed
描述了 N-羟基邻苯二甲酰亚胺酯与不同 N-杂环化合物的氧化还原中性偶联的可见光促进协议。该反应通过 N-羟基邻苯二甲酰亚胺酯的还原脱羧产生的烷基自由基中间体进行。与最初的 Minisci 协议相比,可以在很大程度上避免多烷基化。机理研究揭示了一种自由基链机制,在某些情况下,即使不添加光催化剂也可以进行。这种有价值的和官能团耐受的反应以中等至极好的产率产生取代的杂环。使用廉价的起始材料和 LED 作为光源是这种 C-C 键形成的关键特征。
Stereoselective and Divergent Construction of β-Thiolated/Selenolated Amino Acids via Photoredox-Catalyzed Asymmetric Giese Reaction
作者:Hongli Yin、Mengjie Zheng、Huan Chen、Siyao Wang、Qingqing Zhou、Qiang Zhang、Ping Wang
DOI:10.1021/jacs.0c04994
日期:2020.8.19
photoredox-catalyzed asymmetric method for the preparation of enantiopure β-thiolated/selenolated aminoacids using a simple chiral auxiliary, which controls the diastereoselectivity of the key alkylation step and acts as an orthogonal protecting group in the subsequent peptide synthesis. Our protocol can be used to prepare a wide range of β-thiolated/selenolated aminoacids on a gram scale, which would otherwise
硫和硒由于其氧化还原活性、高亲核性和酰基转移能力而在生物学中占有重要地位。硫醇化/硒化氨基酸,包括半胱氨酸、硒代半胱氨酸及其衍生物,在调节蛋白质的构象和功能方面发挥着关键作用,并作为肽设计和生物偶联的重要基序。不幸的是,获得对映体纯的 β-硫醇化/硒化氨基酸的通用且简明的方法仍然是一个未解决的问题。在此,我们提出了一种光氧化还原催化的不对称方法,使用简单的手性助剂制备对映体纯的 β-硫醇化/硒化氨基酸,它控制关键烷基化步骤的非对映选择性,并在随后的肽合成中充当正交保护基。我们的协议可用于在克规模上制备各种 β-硫醇化/硒化氨基酸,否则使用传统方法很难获得。通过制备一系列肽基硫醇/硒醇类似物,包括细胞色素 c 氧化酶亚基蛋白 7C 和催产素,我们的化学作用得到进一步强调和验证。