In the presence of BiCl3–Zn(0), nearly equimolar amounts of allyl bromide reacted with carbonyl compounds containing a carboxyl group to afford the corresponding homoallylic alcohols having a carboxyl group or the intramolecular dehydrated lactones in good yields.
Anchimeric‐Assisted Spontaneous Hydrolysis of Cyanohydrins Under Ambient Conditions: Implications for Cyanide‐Initiated Selective Transformations
作者:Jayasudhan Reddy Yerabolu、Charles L Liotta、Ramanarayanan Krishnamurthy
DOI:10.1002/chem.201701497
日期:2017.6.27
spontaneous hydrolysis is affected by an intramolecular proton transfer and an intramolecular 5-exo-dig attack, but with a twist. In the case of β-keto acids, the hydrolysis is mediated by the neighboring carboxylic acid group only at pH values less than 7, whereas in the case of γ-keto-alcohols the hydrolysis is mediated by the neighboringhydroxylgroup only at pH values greater than 7. The results, in combination
β-Lactam Synthesis by Ugi Reaction of β-Keto Acids in Aqueous Solution
作者:Michael C. Pirrung、Koushik Das Sarma
DOI:10.1055/s-2004-825606
日期:——
A novel protocol for accelerating Ugi reactions in aqueous solution enables the application of the reaction to β-keto acids. This process results in the preparation of even highly strained ring-fused β-lactams.
一种新颖的水相乌基反应加速协议使该反应能够应用于β-酮酸。该过程能制备出高度紧张的环状β-内酰胺。
Lipase CAL-B does not catalyze a promiscuous decarboxylative aldol addition or Knoevenagel reaction
作者:Andrew S. Evitt、Uwe T. Bornscheuer
DOI:10.1039/c0gc00505c
日期:——
decarboxylative aldol addition and Knoevenagel reaction between 4-nitrobenzaldehyde (4-NBA) and ethyl acetoacetate. We here provide experimental evidence that CAL-B simply catalyzedhydrolysis of the ester yielding the free acetoaceticacid, which under the reaction conditions readily reacts with 4-NBA to the described products.
Isolation and Structural Characterization of New Anthocyanin-Derived Yellow Pigments in Aged Red Wines
作者:Jingren He、Celestino Santos-Buelga、Artur M. S. Silva、Nuno Mateus、Victor de Freitas
DOI:10.1021/jf062325q
日期:2006.12.1
structures of these pigments correspond to methyl-linked pyranomalvidin 3-glucoside and its respective coumaroyl glucoside derivative. They were shown to arise from the reaction between acetoacetic acid and genuine grape anthocyanins. Isolation and NMR identification using 1D and 2D NMR techniques are reported for the first time for this new family of anthocyanin-derived yellow pigments occurring in red