41998-14-5Relevant articles and documents
Mechanically induced solvent-free esterification method at room temperature
Zheng, Lei,Sun, Chen,Xu, Wenhao,Dushkin, Alexandr V.,Polyakov, Nikolay,Su, Weike,Yu, Jingbo
, p. 5080 - 5085 (2021/02/05)
Herein, we describe two novel strategies for the synthesis of esters, as achieved under high-speed ball-milling (HSBM) conditions at room temperature. In the presence of I2 and KH2PO2, the reactions afford the desired esterification derivatives in 45% to 91% yields within 20 min of grinding. Meanwhile, using KI and P(OEt)3, esterification products can be obtained in 24% to 85% yields after 60 min of grinding. In addition, the I2/KH2PO2 protocol was successfully extended to the late-stage diversification of natural products showing the robustness of this useful approach. Further application of this method in the synthesis of inositol nicotinate was also discussed. This journal is
Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
, p. 66 - 71 (2020/11/18)
The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
Tukacs, József M.,Marton, Bálint,Albert, Eszter,Tóth, Imre,Mika, László T.
, (2020/08/11)
Fossil-based solvents and triethylamine as a toxic and volatile base were successfully replaced with γ-valerolactone as a non-volatile solvent and K2CO3 as inorganic base in the alkoxy- and aryloxycarbonylation of aryl iodides using phosphine-free Pd catalyst systems. By this, the traditional systems were not simply replaced but also significantly improved. In the study, the effects of different reaction parameters, i.e. the use of several other solvents, the temperature, the carbon monoxide pressure, the base and the catalyst concentrations, were evaluated in details on the efficiency of the carbonylations. To gather some information on the mechanism of these reactions, the effects of the electronic parameters (σ) of various aromatic substituents of the aryl iodides as well as the influence of para-substitution of phenol were investigated on the activity. For a comparison, the aryl-substituted aryl iodides were also reacted with methanol and aryl iodide was also alkoxycarbonylated using several different lower alcohols. From the observed correlations between the electronic parameters of the aromatic substituents and the rates, it appears that the rate determining step is the oxidative addition of Ar–I to Pd0, provided that sufficient amounts of nucleophiles are present for the ester formation. If this is not the case, the rate of nucleophile attack might determine the overall rate.
