能够形成碳-氮、碳-氧和碳-碳键的反应是合成化学的核心。然而,通常需要底物预功能化来实现此类转化,而无需强制反应条件。因此,开发丰富的原料化学品的直接偶联方法对于快速构建复杂的分子支架是非常必要的。在这里,我们报道了在可见光照射下羧酸与多种亲核试剂的铜介导的净氧化脱羧偶联。初步机理研究表明,该反应中的相关生色团是原位组装的 Cu( ii ) 羧酸盐物种。我们提出,可见光激发配体到金属的电荷转移(LMCT)状态会导致自由基脱羧过程,从而引发氧化交叉偶联。该反应适用于多种偶联伙伴,包括复杂的药物分子,表明这种交叉亲核偶联策略将促进快速化合物库合成,以发现新的药物制剂。
Site‐Selective Alkoxylation of Benzylic C−H Bonds by Photoredox Catalysis
作者:Byung Joo Lee、Kimberly S. DeGlopper、Tehshik P. Yoon
DOI:10.1002/anie.201910602
日期:2020.1.2
strategies for C-N and C-C bond formation. In particular, almost all methods for the incorporation of alcohols by C-H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C-H bonds with a wide range of oxygen
A direct catalytic substitution of various allylic and benzylic alcohols with synthetically useful, but acid-sensitive Boc, Bus, and Dios protected amine nucleophiles, which have not been well utilized for Lewis acid catalysis, with various functionalities (OTBS, OTHP, etc.) was efficiently catalyzed by 1 mol% of Au(III) under mild conditions.
Directaminations of allylic alcohols, benzylic alcohols, and benzhydrols with electron‐withdrawing (F, Br, I, NO2, or CN) substituents were efficiently catalyzed by aluminumtriflate [Al(OTf)3] to afford the corresponding biarylamines in high yield, and the dibromo‐substituted product was further transformed into letrozole.
Direct Amination of Benzylic Pinacol Boronates by an Aminoazanium
作者:Chao Liu、Jianeng Xu、Yucheng Qin
DOI:10.1055/a-2028-5646
日期:——
A practical stereospecific directamination of benzylic pinacol boronates was achieved by using 4-amino-4-methylmorpholinium iodide as a new amination reagent and cesium carbonate as the base. After amination, an in situ reductive N-alkylation with an aldehyde proceeded well to produce secondary amines.
A simple and practical method for the synthesis of primary alkylamines by direct functionalization of hydrocarbons is described. The N-Boc-protected alkylamines are readily prepared from tert-butyl (trimethylsilyl)carbamate and N-fluorobenzenesulfonimide in the presence of a Cu(I) catalyst at low catalyst loadings. Advantageously, this process proceeds free of any additive such as auxiliary bases/acids