Electrochemical Decarboxylative <i>N</i>-Alkylation of Heterocycles
作者:Tao Sheng、Hai-Jun Zhang、Ming Shang、Chi He、Julien. C. Vantourout、Phil. S. Baran
DOI:10.1021/acs.orglett.0c02799
日期:2020.10.2
An operationally simple method to employ nonactivated carboxylic acids as alkylating agents in the N-alkylation of heterocycles is reported through an electrochemically driven anodic decarboxylative process. A wide substrate scope across a range of heterocycles is demonstrated along with a series of applications that significantly reduce the step count required to access such medicinally relevant structures
Ligand‐Enabled β‐C–H Arylation of α‐Amino Acids Without Installing Exogenous Directing Groups
作者:Gang Chen、Zhe Zhuang、Gen‐Cheng Li、Tyler G. Saint‐Denis、Yi Hsiao、Candice L. Joe、Jin‐Quan Yu
DOI:10.1002/anie.201610580
日期:2017.2
Herein we report acid‐directed β‐C(sp3)‐Harylation of α‐amino acids enabled by pyridine‐type ligands. This reaction does not require the installation of an exogenous directinggroup, is scalable, and enables the preparation of Fmoc‐protected unnatural amino acids in three steps. The pyridine‐type ligands are crucial for the development of this new C(sp3)‐Harylation.
General Access to Modified α‐Amino Acids by Bioinspired Stereoselective γ‐C−H Bond Lactonization
作者:Laia Vicens、Massimo Bietti、Miquel Costas
DOI:10.1002/anie.202007899
日期:2021.2.23
show that the use of bioinspired manganese catalysts and H2O2 under mild conditions, provides access to modified α‐amino acids via γ‐C−H bond lactonization. The system can efficiently target 1°, 2° and 3° γ‐C−H bonds of α‐substituted and achiral α,α‐disubstituted α‐amino acids with outstanding site‐selectivity, good to excellent diastereoselectivity and (where applicable) enantioselectivity. This methodology
α‐氨基酸代表了宝贵的一类天然产物,被用作生物和化学合成的基础。由于可用的天然氨基酸数量有限,并且它们在蛋白质组学,诊断,药物递送和催化中的广泛应用,对开发制备修饰的类似物的方法的需求日益增加。在这里,我们表明使用了生物启发性的锰催化剂和H 2 O 2在温和的条件下,可通过γ-C-H键内酯化作用获得修饰的α-氨基酸。该系统可有效靶向α-取代的和非手性α,α-二取代的α-氨基酸的1°,2°和3°γ-C-H键,具有出色的位点选择性,良好的非对映选择性和(如果适用)对映选择性。该方法可以被认为是完善的有机金属程序的替代方法。
Ligand-Enabled β-C–H Arylation of α-Amino Acids Using a Simple and Practical Auxiliary
作者:Gang Chen、Toshihiko Shigenari、Pankaj Jain、Zhipeng Zhang、Zhong Jin、Jian He、Suhua Li、Claudio Mapelli、Michael M. Miller、Michael A. Poss、Paul M. Scola、Kap-Sun Yeung、Jin-Quan Yu
DOI:10.1021/ja512690x
日期:2015.3.11
Pd-catalyzed β-C-H functionalizations of carboxylic acid derivatives using an auxiliary as a directinggroup have been extensively explored in the past decade. In comparison to the most widely used auxiliaries in asymmetric synthesis, the simplicity and practicality of the auxiliaries developed for C-H activation remains to be improved. We previously developed a simple N-methoxyamide auxiliary to direct
Ligand-accelerated enantioselective methylene C(sp
<sup>3</sup>
)–H bond activation
作者:Gang Chen、Wei Gong、Zhe Zhuang、Michal S. Andrä、Yan-Qiao Chen、Xin Hong、Yun-Fang Yang、Tao Liu、K. N. Houk、Jin-Quan Yu
DOI:10.1126/science.aaf4434
日期:2016.9.2
Effective differentiation of prochiral carbon–hydrogen (C–H) bonds on a single methylene carbon via asymmetric metal insertion remains a challenge. Here, we report the discovery of chiral acetyl-protected aminoethyl quinoline ligands that enable asymmetric palladium insertion into prochiral C–H bonds on a single methylene carbon center. We apply these palladium complexes to catalytic enantioselective