A green and efficient visible-light promoted oxidative desulphurisation protocol has been proposed for the construction of unsymmetrical ureas under mild conditions with broad substrate scope and good functional group tolerance. Most appealingly, the reaction can proceed smoothly without adding any strong oxidants. Control experiments and computational studies support a mechanism involving waterassisted in situ generation of thioureas and photocatalytic oxidative desulphurisation. The present method provides a promising synthesis strategy for the formation of diverse and useful unsymmetrical urea derivatives in the fields of pharmaceutical and synthetic chemistry.

One-pot methylenation−cyclization employing two molecules of CO2 with enaminones and primary aromatic amines was discussed for the first time to access cyclized products. This 1,5,7-triazabicyclo[4.4.0]dec-5-ene and ZnCl2- catalyzed procedure was characterized by the selective conversion of two molecules of CO2 into methylene groups in a multicomponent cyclization reaction. According to the computational study and control experiments, the reaction might proceed through the generation of bis(silyl)acetal and condensation of arylamine and aza-Diels−Alder processes. Moreover, the resulting products will probably be potential organic building blocks with adjustable photophysical properties.

The Lewis acidic B(C6F5)3 was recently demonstrated to be effective for the C−H alkylation of phenols with diazoesters. The method avoids the general hydroxyl activation in transition-metal catalysis. Ortho-selective C−H alkylation occurs regardless of potential para-selective C−H alkylation and O−H alkylation. In the present study, a theoretical calculation was carried out to elucidate the reaction mechanism and the origin of chemo- and regio-selectivity. It is found that the previously proposed B(C6F5)3/N or B(C6F5)3/C bonding-involved mechanisms are not favorable, and a more favored one involves the B(C6F5)3/CO bonding, ratedetermining N2 elimination, selectivity-determining electrophilic attack, and proton transfer steps. Meanwhile, the new mechanism is consistent with KIE and competition experiments. The facility of the mechanism is attributed to two factors. First, the B(C6F5)3/CO bonding reduces the steric hindrance during electrophilic attack. Second, the bonding forms the co

The Rh(III)-catalyzed oxidative coupling of oxime ether (S1) and cyclopropanol (S2) with Cu(II) as the oxidant features the combination of C−H activation and strained ring opening. The sequential order of C−H activation versus ring opening was investigated with the aid of density functional theory calculations. Prior ring opening due to the release of ring strain is found to be favored over the prior C−H activation. For the prior ring-opening mechanisms, the outer-sphere concerted metalation− deprotonation (CMD) mechanism in C−H bond activation is energetically favored. The outer-sphere CMD mechanism proposed in this work favors solvent effects and affords the N→Rh binding that allows a directing role of the Schiff base group. In conclusion, the reaction was suggested to undergo prior ring opening followed by C−H activation via the outer-sphere CMD mechanism.

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.

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.

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.

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.

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.

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.

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.

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.