A new electrochemical zinc metal activation method based on the cathodic reduction of a catalytic amount of zinc bromide in the presence of a zinc anode is described. This procedure is applied to the coupling of α-bromoesters with nitriles, and affords β-ketoesters in good yield.
Scope and Optimization of the Double Knorr Cyclization:
Synthesis of Novel Symmetrical and Unsymmetrical Tricyclic
1,8-Diazaanthraquinones
作者:Dianqing Sun、Allan Prior
DOI:10.1055/s-0036-1589134
日期:2018.2
thereof via doubleKnorrcyclization of di-β-ketoanilide precursor substrates is reported. The scope and generality of the doubleKnorrcyclization were investigated along with an optimization study. The doubleKnorrcyclization was found to be sensitive to steric bulk on precursor substrates. In addition, the presence of a 5-hydroxy group on the 1,3-di-β-ketoanilide facilitated the doubleKnorr cyclization
Chiral C 2-Symmetric Iodoarene-Catalyzed Asymmetric α-Oxidation of β-Keto Esters
作者:Yan Xiong、Vincent Coeffard、Yangyang Feng、Ruofeng Huang、Liangzhen Hu
DOI:10.1055/s-0035-1561442
日期:——
of α-substituted β-ketoesters promoted by C 2-symmetric iodoarenes as chiral agents and MCPBA as the oxidant is described. By a careful screening of the reaction conditions, promising enantiomeric excesses and moderate-to-good yields were obtained for the synthesis of β-ketoesters containing a stereogenic center. The catalytic asymmetric oxidation of α-substituted β-ketoesters promoted by C 2-symmetric
Synthesis of diazaquinomycin a and b: the first double knorr cyclization
作者:T.Ross Kelly、Jeffrey A. Field、Qun Li
DOI:10.1016/0040-4039(88)85288-2
日期:1988.1
The first syntheses of diazaquinomycin A (1) and diazaquinomycinB (11) are described. The key reaction is the tandem doubleKnorr cyclizalion/oxidation of 10 to 1 (Eq. 1)
Decarboxylative Claisen Condensations with Substituted Malonic Acid Half Oxyesters
作者:Marc Presset、Tania Xavier、Parvine Tran、Apolline Gautreau、Erwan Le Gall
DOI:10.1055/a-1950-5110
日期:2023.2
A decarboxylative Claisen condensation involving substituted malonicacid half oxyesters (SMAHOs) as pronucleophiles has been developed. The addition of their magnesium enolates to various acyl donors allows the synthesis of functionalized α-substituted β-keto esters in moderate to excellent yields (13–96%). In addition to acyl chlorides and acid anhydrides, these conditions proved efficient for the