The recent Ir/Pd co-catalyzed photo carboxylation of aromatic halides with CO_(2) has shown high efficiency and excellent functional group tolerance for preparing aromatic carboxylic acids and esters.With the aid of d...The recent Ir/Pd co-catalyzed photo carboxylation of aromatic halides with CO_(2) has shown high efficiency and excellent functional group tolerance for preparing aromatic carboxylic acids and esters.With the aid of density functional theory(DFT)calculations,the carboxylation starts with two parallel steps,i.e.,oxidative addition of aromatic halides on Pd~0 and reductive quenching of the photocatalyst Ir(ppy)_(2)(dtbpy)~+with amine.Thereafter,a successive oxidation of Pd~Ⅱwith the amine radical(generated by the reaction of cationic radical amine and Cs_(2) CO_(3)and Ir~Ⅱspecies occurs to generate Pd~0,from which the carboxylation occurs easily via a coordination,Pd-C insertion step.The release of the carboxylate product then regenerates the catalyst.展开更多
The precise synthesis of planar chiral pillar[n]arenes(PAs)faces significant challenges due to their inherent dynamic racemization induced by rapid molecular flipping.To address this issue and enhance conformational s...The precise synthesis of planar chiral pillar[n]arenes(PAs)faces significant challenges due to their inherent dynamic racemization induced by rapid molecular flipping.To address this issue and enhance conformational stability of these macrocycles,we have developed a strategic approach involving the introduction of sterically bulky aryl(sp^(2))substituents at the molecular rims through dynamic kinetic resolution(DKR).A series of robust and chirality-aligned homo-and hetero-diaryl PAs(n=5,6)were achieved with excellent enantioselectivity(>95%ee)via Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions.Mechanism study revealed axial steric hindrance,rather than radial substitution,governs conformational chirality-locking in pillar[n]arenes.This work not only provides an attractive protocol for the enantioselective synthesis of planar chiral pillar[n]arenes,but also enriches the library of macrocycles for promising applications in chiral molecular machines,enantioselective sensors,and chiral luminescent materials.展开更多
A highly selective palladium-catalyzed carbonylation of 2-alkynylanilines bearing an amide moiety to condensed six-membered heterocyclic structures has been developed under mild conditions(room temperature and atmosph...A highly selective palladium-catalyzed carbonylation of 2-alkynylanilines bearing an amide moiety to condensed six-membered heterocyclic structures has been developed under mild conditions(room temperature and atmospheric pressure of CO).The carbonylative protocol is also compatible with CO surrogates,such as benzene-1,3,5-triyl triformate(TFBen)or the newly developed calix[6]arenes functionalized with six formate groups(CLX[6]CO),which are both capable to release CO in situ.A series of tricyclic fused heterocycles containing the important oxazino-quinolinone scaffold have been selectively obtained(only the 6-endo-dig cyclization mode has been observed)in good to excellent yields(up to 99%).展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.21672001,51961135104)the technical support of high-performance computing platform of Anhui University。
文摘The recent Ir/Pd co-catalyzed photo carboxylation of aromatic halides with CO_(2) has shown high efficiency and excellent functional group tolerance for preparing aromatic carboxylic acids and esters.With the aid of density functional theory(DFT)calculations,the carboxylation starts with two parallel steps,i.e.,oxidative addition of aromatic halides on Pd~0 and reductive quenching of the photocatalyst Ir(ppy)_(2)(dtbpy)~+with amine.Thereafter,a successive oxidation of Pd~Ⅱwith the amine radical(generated by the reaction of cationic radical amine and Cs_(2) CO_(3)and Ir~Ⅱspecies occurs to generate Pd~0,from which the carboxylation occurs easily via a coordination,Pd-C insertion step.The release of the carboxylate product then regenerates the catalyst.
基金financial support from the Natural Science Foundation of Ningxia(Nos.2024AAC03023 and 2024AAC03024)。
文摘The precise synthesis of planar chiral pillar[n]arenes(PAs)faces significant challenges due to their inherent dynamic racemization induced by rapid molecular flipping.To address this issue and enhance conformational stability of these macrocycles,we have developed a strategic approach involving the introduction of sterically bulky aryl(sp^(2))substituents at the molecular rims through dynamic kinetic resolution(DKR).A series of robust and chirality-aligned homo-and hetero-diaryl PAs(n=5,6)were achieved with excellent enantioselectivity(>95%ee)via Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions.Mechanism study revealed axial steric hindrance,rather than radial substitution,governs conformational chirality-locking in pillar[n]arenes.This work not only provides an attractive protocol for the enantioselective synthesis of planar chiral pillar[n]arenes,but also enriches the library of macrocycles for promising applications in chiral molecular machines,enantioselective sensors,and chiral luminescent materials.
基金from the equipment and framework of the COMP-HUB Initiative,funded by the“Departments of Excellence"program of the Italian Ministry for Education,University and Research(MIUR,2018-2022)"ECOSISTER"funded under the National Recovery and Resilience Plan(NRRP),Mission 04 Component 2 Investment 1.5-NextGenerationEU(Call for tender n.3277,30/12/2021Award Number 0001052,dated 23/06/2022).
文摘A highly selective palladium-catalyzed carbonylation of 2-alkynylanilines bearing an amide moiety to condensed six-membered heterocyclic structures has been developed under mild conditions(room temperature and atmospheric pressure of CO).The carbonylative protocol is also compatible with CO surrogates,such as benzene-1,3,5-triyl triformate(TFBen)or the newly developed calix[6]arenes functionalized with six formate groups(CLX[6]CO),which are both capable to release CO in situ.A series of tricyclic fused heterocycles containing the important oxazino-quinolinone scaffold have been selectively obtained(only the 6-endo-dig cyclization mode has been observed)in good to excellent yields(up to 99%).
