Synthesis of Enantiopure Unnatural Amino Acids by Metallaphotoredox Catalysis
作者:Tomer M. Faraggi、Caroline Rouget-Virbel、Juan A. Rincón、Mario Barberis、Carlos Mateos、Susana García-Cerrada、Javier Agejas、Oscar de Frutos、David W. C. MacMillan
DOI:10.1021/acs.oprd.1c00208
日期:2021.8.20
wide array of optically pure unnatural amino acids. This method utilizes a photocatalytic cross-electrophile coupling between a bromoalkyl intermediate and a diverse set of aryl halides to produce artificial analogues of phenylalanine, tryptophan, and histidine. The reaction is tolerant of a broad range of functionalities and can be leveraged toward the scalable synthesis of valuable pharmaceutical scaffolds
Metallaphotoredox Perfluoroalkylation of Organobromides
作者:Xiangbo Zhao、David W. C. MacMillan
DOI:10.1021/jacs.0c09977
日期:2020.11.18
Ruppert-Prakash type reagents (TMSCF3, TMSC2F5, and TMSC3F7) are readily available, air-stable, and easy-to-handle fluoroalkyl sources. Herein, we describe a mild, copper-catalyzed cross-coupling of these fluoroalkyl nucleophiles with aryl and alkyl bromides to produce a diverse array of trifluoromethyl, pentafluoroethyl, and heptafluoropropyl adducts. This light-mediated transformation proceeds via
A radical approach to the copper oxidative addition problem: Trifluoromethylation of bromoarenes
作者:Chip Le、Tiffany Q. Chen、Tao Liang、Patricia Zhang、David W. C. MacMillan
DOI:10.1126/science.aat4133
日期:2018.6
Arenes get a light boost onto copper Insertion of palladium into an aryl halide bond is the first step in numerous variants of cross-coupling chemistry used to make carbon-carbon bonds. Copper is an appealing alternative catalyst for such reactions because of its abundance and downstream reactivity profile. However, this preliminary step, termed oxidative addition, is often prohibitively slow for the
The reaction of 2,5‐dibromopyrazine with N‐Lithium pyrazolate in a 1:2 ratio leads to a mixture of 2‐bromo‐5‐(1H‐pyrazol‐1‐yl)pyrazine (I) and 2,5‐di(1H‐pyrazol‐1‐yl)pyrazine (II). The structures of I and II are highly planar. Two absorption bands can be observed for the compounds in the UV‐Vis region, having ε in the order of 104 m−1 cm−1. TD‐DFT computed results support the nature of the lower energy
2,5-二溴吡嗪与 N-吡唑酸锂以 1:2 的比例反应生成 2-溴-5-(1H-吡唑-1-基)吡嗪 (I) 和 2,5-二( 1H-吡唑-1-基)吡嗪 (II)。I 和 II 的结构是高度平面的。在 UV-Vis 区域可以观察到化合物的两个吸收带,ε 约为 104 m-1 cm-1。TD-DFT 计算结果支持较低能量吸收的性质,如 πpyrazine→π*pyrazine 跃迁,包括 I 的额外配位内电荷转移跃迁(πpyrazol→π*pyrazine)。在 280 或 320 nm 激发时,两种化合物的发射几乎不受溶剂极性或氧存在的影响,在 350-450 nm 区域显示两个 I 带和一个 II 带。II 的发射遵循单指数衰减,而 I 的发射遵循双指数定律,从π吡嗪→π*吡嗪和π吡唑→π*吡嗪跃迁假设。I 和 II 的光降解遵循一级动力学,常数分别为 1.18 × 10-2 min-1 和
Diphenylsilylsilanolates Enable the Transfer of a Wide Range of Silyl Groups
Development of silylating reagents that can transfer a wide range of silyl groups has been a long-standing challenge. Herein we report sodium diphenylsilylsilanolates as new stable and handy silylating reagents that could be synthesized from chlorosilanes. The new reagents retain the ability of dimethylsilylsilanolates for the delivery of a variety of silyl groups in palladium-catalyzed silylation