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。
Nickel-Mediated Synthesis of Non-Anomeric <i>C</i>-Acyl Glycosides through Electron Donor–Acceptor Complex Photoactivation
作者:Marcos Escolano、María Jesús Cabrera-Afonso、Maria Ribagorda、Shorouk O. Badir、Gary A. Molander
DOI:10.1021/acs.joc.1c03041
日期:2022.4.1
The preparation of nonanomeric C-acyl-saccharides has been developed from two different carboxylic acid feedstocks. This transformation is driven by the synergistic interaction of an electron donor–acceptor complex and Ni catalysis. Primary-, secondary-, and tertiary redox-active esters are incorporated as coupling partners onto preactivated pyranosyl- and furanosyl acids, preserving their stereochemical
report a copper metallaphotocatalytic 1,2-difunctionalization of terminal alkynes with N-hydroxyphthalimide (NHP) esters and readily available silyl reagents (TMSCN and TMSNCS) to access stereodefinedtrisubstitutedalkenes, including (E)-alkenyl nitriles and thiocyanates. The reaction proceeds with excellent anti-stereoselectivity and demonstrates broad compatibility with a wide range of terminal alkynes
作者:Qing Wang、Xiangzhang Tao、Shengyang Ni、Yi Pan、Yi Wang
DOI:10.1021/acs.orglett.3c02082
日期:2023.8.11
establishing C(sp3)–N bonds from alkyl substrates in cross-couplingchemistry using palladium and nickel catalysts. Therefore, the methods of constructing C(sp3)–N bonds remain rare from alkyl electrophiles. The existing routes are limited to copper catalysis and photoredox catalysis. Here, we demonstrate an alternative amination strategy for rapid construction of C(sp3)–N bonds from accessible alkyl electrophiles
双分子亲核取代S N 2 是烷基亲电试剂胺化最早也是最重要的手段;其实际应用很大程度上限于初级或活化基质。此外,持续的挑战在于使用钯和镍催化剂在交叉偶联化学中从烷基底物建立C(sp 3 )–N键。因此,从烷基亲电子试剂构建C(sp 3 )–N键的方法仍然很少。现有的路线仅限于铜催化和光氧化还原催化。在这里,我们展示了一种替代的胺化策略,用于从可接近的烷基亲电子试剂中快速构建 C(sp 3 )–N 键,该策略在镍催化下通过 Ni (III) 物种高效还原消除用作自由基前体。