Regioselectivity in the ring-opening β-scission of 2-phenyl-1,3-dioxan-2-yl radicals derived from bicyclic benzylidene acetals
作者:Yudong Cai、Hai-Shan Dang、Brian P. Roberts
DOI:10.1039/b208200b
日期:——
2-phenyl-1,3-dioxan-2-yl radicals with fused cyclohexane or cyclopentane rings and there are two modes of cleavage for each radical, to give either a primary or a secondary 3-benzoyloxyalkyl radical. The regioselectivity of β-scission differs markedly depending on whether the ring junction is cis or trans, such that the trans-isomer gives preferentially the primary alkyl radical while the cis-isomer affords
Esterification of Tertiary Amides by Alcohols Through C−N Bond Cleavage over CeO
<sub>2</sub>
作者:Takashi Toyao、Md. Nurnobi Rashed、Yoshitsugu Morita、Takashi Kamachi、S. M. A. Hakim Siddiki、Md. A. Ali、A. S. Touchy、Kenichi Kon、Zen Maeno、Kazunari Yoshizawa、Ken‐ichi Shimizu
DOI:10.1002/cctc.201801098
日期:2019.1.9
process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT‐IR and temperatureprogrammeddesorption using probe molecules demonstrate that both acidic and
The oxidative esterification of various aldehydes with alcohols could be achieved by a heterogeneous iron(III) catalyst supported on a ring-like POM inorganic ligand under mild conditions, affording the corresponding esters, including several drug molecules and natural products, in high yields. ESI-MS and control experiments demonstrated that POM-FeV(O) was the active catalytic species and the plausible
Synthesis of Esters from Stable and Convenient Sulfoxonium Precursors under Catalyst- and Additive-Free Conditions
作者:Yang Yuan、Xiao-Feng Wu
DOI:10.1055/s-0039-1690157
日期:2019.9
A convenient and efficient procedure for the construction of esters from stable sulfoxonium ylides and alcohols has been developed. This protocol presents a broad substrate scope and good yields of the desired esters can be isolated. Notably, no catalyst, oxidant, base or any other additive is required.
Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
作者:Changyu Huang、Jinpeng Li、Jiaquan Wang、Qingshu Zheng、Zhenhua Li、Tao Tu
DOI:10.1007/s11426-020-9883-3
日期:2021.1
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