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44. Theoretical study on the base-controlled selective linear or branched ortho-alkylation of azines  catalyzed by rhodium: Mechanisms and the role of base
44. Theoretical study on the base-controlled selective linear or branched ortho-alkylation of azines catalyzed by rhodium: Mechanisms and the role of base
The detailed theoretical study on the mechanism of the alkylation of 3-trifluoromethylpyridine with acrylamide in the [RhI]/dppe catalytic system is reported, with the aid of the density functional theory (DFT) calculations. It is found that the additive bases play a critical role in switching the regioselectivity. The origin of the regioselectivity involved in these reactions was probed by performing distortion-interaction analysis. For reaction A with KOPiv as the base, the outer-sphere concerted-metallative-deprotonation (CMD) pathway is calculated to be a bit more favorable kinetically compared with the oxidative addition (OA) one and the two mechanisms are competitive. The regioselectivity in this reaction is predicted to be determined by the distortion energies of the migratory insertion transition states. In contrast, for reaction B with K3PO4 as the base, the feasible pathway is the OA one, and the corresponding interaction energies for the olefin migratory insertion into Rh–H
2024-04-23
43. Catalyst-free synthesis of α-thioacrylic acids via cascade thiolation and  1,4-aryl migration of aryl alkynoates at room temperature
43. Catalyst-free synthesis of α-thioacrylic acids via cascade thiolation and 1,4-aryl migration of aryl alkynoates at room temperature
A simple and facile catalyst-free method for the construction of α-thioacrylic acids has been developed from readily-available aryl alkynoates and thiols at room temperature. Various α-thioacrylic acids could be conveniently and efficiently obtained in moderate to good yields via cascade thiolation and 1,4-aryl migration of aryl alkynoates in the absence of any catalyst and additive.
2024-04-23
42. A DFT mechanistic study on gold(I)-catalyzed cascade reaction of aminaloalkyne  involving Petasis-Ferrier cyclization
42. A DFT mechanistic study on gold(I)-catalyzed cascade reaction of aminaloalkyne involving Petasis-Ferrier cyclization
The reaction mechanism of gold(I)-catalyzed cascade reaction of aminaloalkynes involving PetasisFerrier arrangement was studied with the aid of density functional theory calculations. Our study showed that two mechanisms proposed by the Patil group and by us are possible. With the substrate bearing a -C≡C-H component the mechanism by us is preferred in which the reaction undergoes first a Petasis-Ferrier rearrangement. With the substrate bearing a -C≡C-Ar component the mechanism by the Patil group is preferred in which the reaction undergoes first a protodeauration step. In summary, both reaction mechanisms are related and reaction substrate governs which pathway is followed.
2024-04-23
41. Unveiling the mechanisms and secrets of chemoselectivities in Au(I)-catalyzed  diazo-based couplings with aryl unsaturated aliphatic alcohols
41. Unveiling the mechanisms and secrets of chemoselectivities in Au(I)-catalyzed diazo-based couplings with aryl unsaturated aliphatic alcohols
Density functional theory (DFT) calculations have been conducted to unravel the mechanisms and chemoselectivities of Au-catalyzed diazo-based couplings with phenyl unsaturated aliphatic alcohols: the propargyl alcohol Ba resulting in the [4 + 1]-cycloaddition product P4a and the allyl alcohol Db giving the [2,3]-σ rearrangement species P5b. P4a formation involves a catalyst interaction with phenyldiazoacetate, N2 release, a hydroxyl O nucleophilic attack of Ba, a [1,4]-H shift, coordination isomerization, 5-endo-dig cyclization, a [4,1]-H shift and a H2O-assisted [1,3]-H shift. After the [4,1]-H shift, the slightly less favorable five-membered ring-opening possibly follows to afford trace P5a ([2,3]-σ rearrangement product), which would be kept in solution due to subsequent irreversible evolution. In addition, the Ba-involved chemoselectivity was probed and explained as follows: (i) both large HIJhydroxyl)⋯C(carbene) electrostatic repulsion and strong three-membered ring strain involved
2024-04-23

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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
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