transition-metal-free direct α-C–H amination of ketones has been developed using commercially available ammonium iodide as the catalyst and sodium percarbonate as the co-oxidant. A wide range of ketone ((hetero)aromatic or nonaromatic ketones) and amine (primary/secondary amines, anilines, or amides) substrates undergo cross-coupling to generate synthetically useful α-amino ketones. The mechanistic studies indicated
the first time to synthesize pharmaceutically important α-aminoketonesfrom readily available benzylic secondary alcohols and amines using N-bromosuccinimide. This new reaction proceeds via three consecutive steps involving oxidation of alcohols, α-bromination of ketones, and nucleophilic substitution of α-bromo ketones to give α-aminoketones. Importantly, this novel one-pot greener reaction avoids
Synthesis and characterization of bisoxazolines- and pybox-copper(<scp>ii</scp>) complexes and their application in the coupling of α-carbonyls with functionalized amines
[(Dm-Pybox)CuBr2] is efficient in catalyzing α-amination of ketones and esters, which tolerates functionality on the carbonyl and amine reaction components.
Simple Catalytic Mechanism for the Direct Coupling of α-Carbonyls with Functionalized Amines: A One-Step Synthesis of Plavix
作者:Ryan W. Evans、Jason R. Zbieg、Shaolin Zhu、Wei Li、David W. C. MacMillan
DOI:10.1021/ja4096472
日期:2013.10.30
The direct alpha-amination of ketones, esters, and aldehydes has been accomplished via copper catalysis. In the presence of catalytic copper(II) bromide, a diverse range of carbonyl and amine substrates undergo fragment coupling to produce synthetically useful alpha-amino-substituted motifs. The transformation is proposed to proceed via a catalytically generated alpha-bromo carbonyl species; nucleophilic displacement of the bromide by the amine then delivers the alpha-amino carbonyl adduct while the catalyst is reconstituted. The practical value of this transformation is highlighted through one-step syntheses of two high-profile pharmaceutical agents, Plavix and amfepramone.