最新资讯

76. Transient Stabilization Effect of CO2 in the Electrochemical  Hydrogenation of Azo Compounds and the Reductive Coupling of α-Ketoesters
76. Transient Stabilization Effect of CO2 in the Electrochemical Hydrogenation of Azo Compounds and the Reductive Coupling of α-Ketoesters
The carbon dioxide (CO2) capture and utilization has attracted a great attention in organic synthesis. Herein, an unpresented transient stabilization effect (TSE) of CO2 is disclosed and well applied to the electrochemical hydrogenation of azo compounds to hydrazine derivatives. Mechanistic experiments and computational studies imply that CO2 can capture azo radical anion intermediates to protect the hydrogenation from potential degradation reactions, and is finally released through decarboxylation. The promotion effect of CO2 was further demonstrated to work in the preliminary study of electrochemical reductive coupling of α-ketoesters to vicinal diol derivatives. For the electrochemical reductive reactions mentioned above, CO2 is indispensable. The presented results shed light on a different usage of CO2 and could inspire novel experimental design by using CO2 as a transient protecting group.
2024-04-23
75. Insights into α-Alkynylation and α-Allenylation of Aldehydes under the  Synergisitic Catalysis of Gold/Amine: A DFT Study
75. Insights into α-Alkynylation and α-Allenylation of Aldehydes under the Synergisitic Catalysis of Gold/Amine: A DFT Study
A mechanistic investigation of α-alkynylation and α- allenylation of aldehydes under the synergistic catalysis of AuCl/ amine was performed using density functional theory (DFT) calculations. For such a reaction that delivers two products, this study reveals that the reaction undergoes such a mechanistic mode: reactants → alkynyl product → allenyl product, implying that the allenyl product cannot be obtained directly from reactants. The product ratio obtained experimentally was rationalized based on the computed results that both products can reversibly interconvert with AuCl as the catalyst and with N-containing Lewis bases as additives such as 4,5-diazafluorenone. For the relative stability of alkynyl versus allenyl compounds, unsaturated substituents are found to favor the allenyl compounds.
2024-04-23
74. Distinctive Mechanistic Scenarios and Substituent Effects of  Gold(I) versus Copper(I) Catalysis for Hydroacylation of Terminal Alkynes with Glyoxal Derivatives
74. Distinctive Mechanistic Scenarios and Substituent Effects of Gold(I) versus Copper(I) Catalysis for Hydroacylation of Terminal Alkynes with Glyoxal Derivatives
Density functional theory (DFT) calculations have been conducted to study the mechanisms, substituent effects, and the role of bases in Au- and Cu-catalyzed hydroacylation of terminal alkyne with glyoxal derivatives. The two reactions, despite being catalyzed by the same group of transition metals, follow distinctive reaction mechanisms. Through the detailed DFT calculations, insights into the mechanisms are obtained, and the substituent effects and the role of the bases are understood.
2024-04-23
73. Mechanistic insight into Cp*Rh(III)-catalyzed Lossen rearrangement vs  C–N reductive elimination for the synthesis of pyridones
73. Mechanistic insight into Cp*Rh(III)-catalyzed Lossen rearrangement vs C–N reductive elimination for the synthesis of pyridones
A comprehensive density functional theory study has been performed on the mechanism of Cp*Rh(III)- catalyzed C–H activation of N-(pivaloyloxy)acrylamide with alkynyl triazene. The calculated results reveal that a concerted Lossen rearrangement/OPiv migration from N to Rh is the most favorable pathway to afford an isocyanate intermediate, where a redox-neutral process is involved without the involvement of a Rh(V)-nitrenoid species. Subsequently, the annulation of a rearranged six-membered ring intermediate is realized through a nucleophilic attack of Rh-bonded carbon on the isocyanate carbon, and this process is likely to be the rate-determining step for the entire catalytic cycle, with an overall energy barrier of 20.5 kcal mol1. In addition, the stepwise OPiv migration from N to Rh and C–N reductive elimination, and vice versa, are competitive to yield a non-rearranged byproduct, which experiences a Rh(III)–Rh(V)–Rh(III) transformation of oxidation state.
2024-04-23

最新资讯

96. Non-C1 Synthon Role of CO2: Promoting Divergent Electrochemical Defluorination
96. Non-C1 Synthon Role of CO2: Promoting Divergent Electrochemical Defluorination
Here, an unpresented non-C1 synthon function of CO2 is reported to facilitate electrochemical defluorination. The introduction of CO2 modulates the electron distribution of the radical anion intermediate generated through one-electron reduction, thereby weakening the reduction potential and facilitating reduction and defluorination. CO2 is released subsequently via spontaneous decarboxylation to complete its promotion role. The presented results shed light on a distinctive utilization of CO2, which may stimulate interest in developing non-C1 synthon functions of CO2.
2025-06-13
95. Transition-Metal-Free Mild and Regioselective Alkylation of Quinoline N-Oxides with Benzylboronates
95. Transition-Metal-Free Mild and Regioselective Alkylation of Quinoline N-Oxides with Benzylboronates
A KOtBu-mediated C2-benzylation of quinoline N-oxides with benzylboronates under mild reaction conditions has been developed. The reaction shows broad scope for both of the quinoline N-oxides and benzylboronates, especially, secondary and tertiary benzylboronates are also compatible with this reaction. DFT calculations indicate that the reaction is promoted by the nucleophilic addition of KOtBu to boronate rather than the deprotonation of benzylic C−H bond with KOtBu.
2025-06-13
94. trans-Ge/B 1,1-Hydroboration of Alkynylgermanes with 9‑BBN
94. trans-Ge/B 1,1-Hydroboration of Alkynylgermanes with 9‑BBN
A 1,1-hydroboration of alkynylgermanes with unique transGe/B stereochemistry under transition-metal-free conditions is reported. Mechanistic studies suggest that a pathway involving α boration followed by a stepwise 1,2-Ge/H shift on the intermediate structurally lies between an alkyne−Ge+ π complex and a typical vinyl cation. The resulting Ge/B bimetallic modules, along with a Ge*/Ge/B trimetallic variant, can be conveniently transformed into trisubstituted olefins through iterative divergent cross-coupling. This work demonstrates that incorporating metalloids into classical organic reactions may offer unconventional chemical selectivity and efficient synthetic applications.
2025-05-25
93. Nickel/Photoredox Catalyzed Aryl-Alkyl Cross-Coupling with Alkyl Boronic Esters as Radical Precursors
93. Nickel/Photoredox Catalyzed Aryl-Alkyl Cross-Coupling with Alkyl Boronic Esters as Radical Precursors
Nickel/photoredox dual catalyzed cross-coupling of aryl halides with alkylboron compounds is one of the effective methodologies for the construction of C(sp2) C(sp3) bonds. Although elegant results have been achieved by using alkyl trifluoroborates as alkyl radical precursors, the generation of alkyl radicals from readily available alkyl boronic esters is still limited due to their high oxidation potential. We disclosed here that activation of alkyl boronic esters by MeOLi is highly efficient for the generation of alkyl radicals under photocatalysis conditions. The reaction featured with a wide substrate scope, high functional group tolerance, and late-stage modification of bioactive substances. In addition, the method was also successfully extended to alkyl boronic acids. Experimental and computational mechanistic studies indicated that the crosscoupling likely proceeds via a Ni(I)-catalyzed pathway.
2024-12-23

最新资讯

96. Non-C1 Synthon Role of CO2: Promoting Divergent Electrochemical Defluorination
96. Non-C1 Synthon Role of CO2: Promoting Divergent Electrochemical Defluorination
Here, an unpresented non-C1 synthon function of CO2 is reported to facilitate electrochemical defluorination. The introduction of CO2 modulates the electron distribution of the radical anion intermediate generated through one-electron reduction, thereby weakening the reduction potential and facilitating reduction and defluorination. CO2 is released subsequently via spontaneous decarboxylation to complete its promotion role. The presented results shed light on a distinctive utilization of CO2, which may stimulate interest in developing non-C1 synthon functions of CO2.
2025-06-13
95. Transition-Metal-Free Mild and Regioselective Alkylation of Quinoline N-Oxides with Benzylboronates
95. Transition-Metal-Free Mild and Regioselective Alkylation of Quinoline N-Oxides with Benzylboronates
A KOtBu-mediated C2-benzylation of quinoline N-oxides with benzylboronates under mild reaction conditions has been developed. The reaction shows broad scope for both of the quinoline N-oxides and benzylboronates, especially, secondary and tertiary benzylboronates are also compatible with this reaction. DFT calculations indicate that the reaction is promoted by the nucleophilic addition of KOtBu to boronate rather than the deprotonation of benzylic C−H bond with KOtBu.
2025-06-13
94. trans-Ge/B 1,1-Hydroboration of Alkynylgermanes with 9‑BBN
94. trans-Ge/B 1,1-Hydroboration of Alkynylgermanes with 9‑BBN
A 1,1-hydroboration of alkynylgermanes with unique transGe/B stereochemistry under transition-metal-free conditions is reported. Mechanistic studies suggest that a pathway involving α boration followed by a stepwise 1,2-Ge/H shift on the intermediate structurally lies between an alkyne−Ge+ π complex and a typical vinyl cation. The resulting Ge/B bimetallic modules, along with a Ge*/Ge/B trimetallic variant, can be conveniently transformed into trisubstituted olefins through iterative divergent cross-coupling. This work demonstrates that incorporating metalloids into classical organic reactions may offer unconventional chemical selectivity and efficient synthetic applications.
2025-05-25
93. Nickel/Photoredox Catalyzed Aryl-Alkyl Cross-Coupling with Alkyl Boronic Esters as Radical Precursors
93. Nickel/Photoredox Catalyzed Aryl-Alkyl Cross-Coupling with Alkyl Boronic Esters as Radical Precursors
Nickel/photoredox dual catalyzed cross-coupling of aryl halides with alkylboron compounds is one of the effective methodologies for the construction of C(sp2) C(sp3) bonds. Although elegant results have been achieved by using alkyl trifluoroborates as alkyl radical precursors, the generation of alkyl radicals from readily available alkyl boronic esters is still limited due to their high oxidation potential. We disclosed here that activation of alkyl boronic esters by MeOLi is highly efficient for the generation of alkyl radicals under photocatalysis conditions. The reaction featured with a wide substrate scope, high functional group tolerance, and late-stage modification of bioactive substances. In addition, the method was also successfully extended to alkyl boronic acids. Experimental and computational mechanistic studies indicated that the crosscoupling likely proceeds via a Ni(I)-catalyzed pathway.
2024-12-23
本站使用百度智能门户搭建 管理登录
鲁ICP备18034280号-1