Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl
Photochemical generation of radicals from alkyl electrophiles using a nucleophilic organic catalyst
作者:Bertrand Schweitzer-Chaput、Matthew A. Horwitz、Eduardo de Pedro Beato、Paolo Melchiorre
DOI:10.1038/s41557-018-0173-x
日期:2019.2
extensively use free radical reactivity for applications in organic synthesis, materials science, and life science. Traditionally, generating radicals requires strategies that exploit the bond dissociation energy or the redox properties of the precursors. Here, we disclose a photochemical catalytic approach that harnesses different physical properties of the substrate to form carbon radicals. We use a nucleophilic
化学家在有机合成,材料科学和生命科学中广泛使用自由基反应性。传统上,产生自由基需要利用键解离能或前体的氧化还原特性的策略。在这里,我们公开了一种光化学催化方法,该方法利用了基材的不同物理特性来形成碳自由基。我们使用亲核性的二硫代氨基甲酸酯阴离子催化剂,配以量身定制的发色单元,以通过S N 2途径活化烷基亲电体。所得的吸收光子的中间体在由可见光诱导的均相裂解时提供自由基。此催化性S N基于2的策略利用了离子化学的基本机理过程,可以从各种底物中获得与经典自由基生成策略不兼容或惰性的开壳中间体的访问权限。我们还描述了该方法温和的反应条件和较高的官能团耐受性如何有利于开发C–C键形成反应,简化市售药物的制备,生物相关化合物的后期精制以及对映选择性自由基催化。
<i>N</i>-Acyl-1-chloro-2,2,2-trifluoroethylamine as a 2,2,2-Trifluoroethylamine-Building Block
The reactions of N-benzoyl- and N-acetyl-1-chloro-2,2,2-trifluoroethylamines with various carbon-nucleophiles gave the corresponding 1-substituted N-acyl-2,2,2-trifluoroethylamines in good yields and the efficient reactivity was applied on the synthesis of 2-acylamino-2-trifluoromethylethanol derivative.
Eine allgemeine Synthesevon C-Perfluoralkyl-glycinen 1 wird beschrieben, die über N-Acyl-aldimine 2, 3-Amino-3-perfluoralkyl-N-acyl-propene- (1) 8 und C- Perfluoralkyl-N-acyl-glycine 9 verläft. Analog läßt sich auch 3.3.3- Trichlor-alanin (13) herstellen.
EINE汇报合成冯Ç -Perfluoralkyl-glycinen 1 wird beschrieben,模具黚Ñ酰基-醛亚胺2,3-氨基-3- perfluoralkyl- Ñ酰基-propene-(1)8 UND Ç - Perfluoralkyl- ñ -酰基甘氨酸9个版本。模拟量约3.3.3-三氯丙氨酸(13)。
Weygand,F. et al., Chemische Berichte, 1966, vol. 99, p. 1944 - 1956