An efficient NMR determination of the enantiomeric excess of the amino acids can be achieved using chloro-bridged dimer R- (+)-{Pd [(eta(5)-C5H5)Fe (eta(5)-C5H3CMe=NAr)] (mu-Cl)}2 (Ar=p-CH3C6H4) (R-1).
An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. ...An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.展开更多
Cyclopalladated ferrocenylimine has been found to be a type of excellent phosphine-free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up t...Cyclopalladated ferrocenylimine has been found to be a type of excellent phosphine-free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up to now. Some commercial emulsifying agents, including the commonly used quaternary ammonium salts, have been proved to be excellent additives in the catalysis of the reactions. Not only aromatic iodide, but also aromatic bromide could be coupled with the olefins. All reactions were able to be conducted in air under refluxing condition.展开更多
文摘An efficient NMR determination of the enantiomeric excess of the amino acids can be achieved using chloro-bridged dimer R- (+)-{Pd [(eta(5)-C5H5)Fe (eta(5)-C5H3CMe=NAr)] (mu-Cl)}2 (Ar=p-CH3C6H4) (R-1).
基金Project supported by the National Natural Science Foundation of China （No. 20772114） and the Innovation Fund for Outstanding Scholar of Henan Province （No. 0621001100）.
文摘An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.
基金Project supported by the National Natural Science Foundation of China(No.20072034)and the Natural Science Foundation of Henan Province(No.004030100).
文摘Cyclopalladated ferrocenylimine has been found to be a type of excellent phosphine-free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up to now. Some commercial emulsifying agents, including the commonly used quaternary ammonium salts, have been proved to be excellent additives in the catalysis of the reactions. Not only aromatic iodide, but also aromatic bromide could be coupled with the olefins. All reactions were able to be conducted in air under refluxing condition.
