66892-79-3Relevant academic research and scientific papers
Environmentally benign metal-free decarboxylative aldol and Mannich reactions
Baudoux, Jerome,Lefebvre, Pierre,Legay, Remi,Lasne, Marie-Claire,Rouden, Jacques
experimental part, p. 252 - 259 (2011/03/18)
Aiming at the development of green and efficient C-C bond formations (aldol and Mannich reactions), the decarboxylative nucleophilic addition of malonic acid half ester to imines or aldehydes under mild metal-free conditions was studied. A careful control of the temperature and the appropriate choice of the organic base allowed us to obtain β-amino esters or β-hydroxy esters including α-substituted and α,α-disubstituted ones in moderate to excellent yields. 1H NMR monitoring of the reaction unveiled two distinct mechanisms depending on the hemimalonate used. With the unsubstituted substrate, a carboxylic acid intermediate was isolated upon acid quench resulting from the nucleophilic addition of the putative enol carboxylate anion of the hemimalonate to imines/aldehydes before CO2 loss. With substituted hemimalonates, the reaction likely involved an enolate which then added to imines/aldehydes or was competitively protonated. According to the base used, the reaction can be carried out either under solvent free-conditions or in an ionic liquid under mild conditions.
Boron Trifluoride Promoted Aldol Reaction of Silyl Ketene Acetals with the Intermediate Generated by the DIBALH Reduction of Carboxylic Acid Esters
Kiyooka, Syun-ichi,Shirouchi, Masashi
, p. 1 - 2 (2007/10/02)
The intermediate generated by the DIBALH reduction of carboxylic acid esters undergoes a boron trifluoride promoted aldol reaction with silyl ketene acetals to afford the corresponding β-hydroxy carboxylic acid esters in good yield.
