57519-78-5Relevant academic research and scientific papers
Reductive Knoevenagel Condensation with the Zn-AcOH System
Ivanov, Konstantin L.,Melnikov, Mikhail Ya.,Budynina, Ekaterina M.
, p. 1285 - 1291 (2020/11/13)
An efficient gram-scale one-pot approach to 2-substituted malonates and related structures is developed, starting from commercially available aldehydes and active methylene compounds. The technique combines Knoevenagel condensation with the reduction of the C=C bond in the resulting activated alkenes with the Zn-AcOH system. The relative ease with which the C=C bond reduction occurs can be traced to the accepting abilities of the substituents in the intermediate arylidene malonates.
Direct Cyclopropanation of α-Cyano β-Aryl Alkanes by Light-Mediated Single Electron Transfer Between Donor–Acceptor Pairs
Li, Jing,Lear, Martin J.,Hayashi, Yujiro
, p. 5901 - 5905 (2021/03/09)
Cyclopropanes are traditionally prepared by the formal [2+1] addition of carbene or radical based C1 units to alkenes. In contrast, the one-pot intermolecular cyclopropanation of alkanes by redox active C1 units has remained unrealised. Herein, we achieve
Overcoming Selectivity Issues in Reversible Catalysis: A Transfer Hydrocyanation Exhibiting High Kinetic Control
Bhawal, Benjamin N.,Ehinger, Christian,Morandi, Bill,Reisenbauer, Julia C.
supporting information, p. 10914 - 10920 (2020/07/13)
Reversible catalytic reactions operate under thermodynamic control, and thus, establishing a selective catalytic system poses a considerable challenge. Herein, we report a reversible transfer hydrocyanation protocol that exhibits high selectivity for the thermodynamically less favorable branched isomer. Selectivity is achieved by exploiting the lower barrier for C-CN oxidative addition and reductive elimination at benzylic positions in the absence of a cocatalytic Lewis acid. Through the design of a novel type of HCN donor, a practical, branched-selective, HCN-free transfer hydrocyanation was realized. The synthetically useful resolution of a mixture of branched and linear nitrile isomers was also demonstrated to underline the value of reversible and selective transfer reactions. In a broader context, this work demonstrates that high kinetic selectivity can be achieved in reversible transfer reactions, thus opening new horizons for their synthetic applications.
A general platinum-catalyzed alkoxycarbonylation of olefins
Beller, Matthias,Dühren, Ricarda,Franke, Robert,Ge, Yao,Huang, Weiheng,Jackstell, Ralf,Liu, Jiawang,Neumann, Helfried,Schneider, Carolin,Yang, Ji
supporting information, p. 5235 - 5238 (2020/07/30)
Hydroxy- and alkoxycarbonylation reactions constitute important industrial processes in homogeneous catalysis. Nowadays, palladium complexes constitute state-of-the-art catalysts for these transformations. Herein, we report the first efficient platinum-catalysed alkoxycarbonylations of olefins including sterically hindered and functionalized ones. This atom-efficient catalytic transformation provides straightforward access to a variety of valuable esters in good to excellent yields and often with high selectivities. In kinetic experiments the activities of Pd- and Pt-based catalysts were compared. Even at low catalyst loading, Pt shows high catalytic activity.
Development of efficient palladium catalysts for alkoxycarbonylation of alkenes
Liu, Jiawang,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
supporting information, p. 12238 - 12241 (2018/11/21)
Herein, we report a general and efficient Pd-catalysed alkoxycarbonylation of sterically hindered and demanding olefins including a variety of tri-, tetra-substituted and 1,1-disubstituted alkenes. In the presence of 1,3-bis(tert-butyl(pyridin-2-yl)phosphanyl)propane L3 or 1,4-bis(tert-butyl(pyridin-2-yl)phosphanyl)butane L4 the desired esters are obtained in good yields and selectivities. Similar transformation is obtained using tertiary ether as showcased in the carbonylation of MTBE to the corresponding linear ester in high yield and selectivity.
Reductive alkylation of active methylene compounds with carbonyl derivatives, calcium hydride and a heterogeneous catalyst
Guyon, Carole,Duclos, Marie-Christine,Sutter, Marc,Métay, Estelle,Lemaire, Marc
, p. 7067 - 7075 (2015/06/25)
A one-pot two-step reaction (Knoevenagel condensation - reduction of the double bond) has been developed using calcium hydride as a reductant in the presence of a supported noble metal catalyst. The reaction between carbonyl compounds and active methylene
Thiazole formation through a modified Gewald reaction
Mallia, Carl J.,Englert, Lukas,Walter, Gary C.,Baxendale, Ian R.
supporting information, p. 875 - 883 (2015/08/24)
The synthesis of thiazoles and thiophenes starting from nitriles, via a modified Gewald reaction has been studied for a number of different substrates. 1,4-Dithiane-2,5-diol was used as the aldehyde precursor to give either 2-substituted thiazoles or 2-substituted aminothiophenes depending on the substitution of the α-carbon to the cyano group.
Cobalt-catalyzed reductive carboxylation of α,β-unsaturated compounds with carbon dioxide
Hayashi, Chika,Hayashi, Takuo,Yamada, Tohru
, p. 862 - 870 (2015/06/25)
The gaseous carbon dioxide incorporation reaction with α,β-unsaturated compounds was examined in the presence of a catalytic amount of bis(acetylacetonato)cobalt(II) and using diethylzinc as a reductant. After screening with various electron-withdrawing g
Atom- and step-economical preparation of reduced knoevenagel adducts using CO as a deoxygenative agent
Kolesnikov, Pavel N.,Usanov, Dmitry L.,Barablina, Evgeniya A.,Maleev, Victor I.,Chusov, Denis
supporting information, p. 5068 - 5071 (2014/12/11)
A highly efficient one-step Rh-catalyzed preparation of reduced Knoevenagel adducts of various aldehydes and ketones with active methylene compounds has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide
Versatile CuI/Pd0 dual catalysis for the synthesis of quaternary α-allylated carbonyl compounds: Development, mechanistic investigations and scope
Nahra, Fady,Mace, Yohan,Boreux, Arnaud,Billard, Francois,Riant, Olivier
supporting information, p. 10970 - 10981 (2014/09/17)
We report herein a versatile cooperative dual catalysis reaction based on a CuI/Pd0 system. Mechanistic investigation shows that every component plays a crucial role in determining the reaction outcome. The reaction is successfully extended to various substrates; such as α,β-unsaturated ketones, malonates and coumarins. The strategy tolerates different substitution patterns and affords good yields for each family of substrates.
