Applications Of MCM-41-supported 1,10-phenanthroline Copper Complexes In Carbon-Carbon And Carbon-Heteroatom Bonds Formation Reactions

The addition reaction of 5-amino-1,10-phenanthroline to 3-isocyanatopropyltriethoxysilane afforded 1-(1,10-phenanthrolidin-5-yl)-3-(3-(triethoxysilyl)propyl)urea ligand(Phen-Si),which was condensed with mesoporous material MCM-41 in toluene and then silylated by Me3 SiCl to generate the 1,10-phenanthroline-functionalized mesoporous material MCM-41(MCM-41-Phen).The latter was reacted with CuSO4 or CuI to give MCM-41-Phen-CuSO4 and MCM-41-Phen-CuI complexes,respectively.Both new heterogeneous copper catalysts were characterized by elemental analysis,ICP-AES,XRD,and so on.The Chan-Lam cross-coupling reaction of arylboronic acids with thiophenols was investigated under the catalysis of MCM-41-Phen-CuSO4.The results show that this heterogeneous copper catalyst exhibits high catalytic activity and the cross-coupling reactions of arylboronic acids with thiophenols proceeded smoothly in ethanol at room temeperature with 40% n-Bu4 NOH as base,yielding a variety of unsymmetric diaryl sulfides in good yield under mild and green conditions.This heterogeneous C–S coupling reaction is suitable for a range of aryboronic acids and various thiophenols.The catalyst can easily be separated and recovered by a simple filtration of reaction solution,and recycled for eight times without significant loss of activity.The C–O coupling reaction between aryl iodides and aliphatic alcohols was studied by using MCM-41-Phen-CuI as catalyst.It was found that C–O coupling reactions of a range of aryl iodides with different aliphatic alcohols in neat alcohol or toluene as solvent proceeded effectively in the presence of 10 mol% MCM-41-Phen-CuI with Cs2CO3 as base to give a variety of aryl alkyl ethers in good to excellent yields.In addition to simple primary alcohols,secondary alcohols,benzylic alcohols,and allylic alcohols were also good substrates.The recycle experiments showed that the catalyst can be easily separated from the product by filtration,and the recovered catalyst can be recycled up to eight times without obvious decrease in the activity.The decarboxylative C–C coupling reaction between aryl iodides or bromides and potassium polyfluorobenzoates was studied by using MCM-41-Phen-CuI as catalyst.The results show that the and decarboxylative C–C coupling reaction of a range of aryl iodides or bromides with various potassium polyfluorobenzoates proceeded smoothly in diglyme or DMAc as solvent at 130 or 160 oC in the presence of 10-20 mol% MCM-41-Phen-CuI,affording a variety of polyfluorobiaryls in excellent yields.This heterogeneous copper catalyst can easily be recovered by filtration,and recycled for at least six times without significant loss of activity,providing a novel,practical and green route to polyfluorobiaryls.MCM-41-immobilized bidentate nitrogen Cu(II)complex [MCM-41-2N-Cu(OAc)2] was prepared according to our previous procedure and utilized as catalyst for the synthesis of [1,2,3]triazolo[1,5-a]pyridines.The results show that the “one-pot” oxidative cyclization reaction of a range of 2-acylpyridines with hydrazine hydrate proceeded effectively in the presence of 5 mol% MCM-41-2N-Cu(OAc)2,yielding a variety of [1,2,3]triazolo[1,5-a] pyridines in good to excellent yields.After repeated use of at least eight times,there is no significant decrease in activity,indicating that the catalyst has high stability and good recyclability.