The first heterogeneous gold(I)-catalyzed [2 + 2 + 1] annulation of terminal alkynes, nitriles, and oxygen atoms has been achieved by using an MCM-41-immobilized phosphine–gold(I) complex as catalyst and 8-methylquinoline N-oxide as oxidant under mild conditions, yielding a variety of 2,5-disubstituted oxazoles in good to excellent yields with broad substrate scope. The new heterogeneous gold(I) catalyst can easily be recovered by simple filtration of the reaction solution and recycled for at least eight times without significant loss of activity.

The first phosphine-free heterogeneous palladium-catalyzed carbonylative cross-coupling of aryl halides with triorganoindiums has been developed that proceeds smoothly under 1 or 2.5 atm of carbon monoxide in THF at 68 °C and provides a general and powerful tool for the synthesis of various valuable unsymmetrical ketones with high atom-economy, good yield, and recyclability of the catalyst. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.

The first phosphine-free heterogeneous palladium(0)-catalyzed cross-coupling of triorganoindiums with acyl chlorides has been developed that proceeds smoothly in THF at 68 °C and provides a general and powerful tool for the synthesis of various valuable aryl ketones and α,β-acetylenic ketones with high atom-economy and high yield. This phosphine-free heterogeneous palladium(0) catalyst can be easily prepared from commercially available reagents and recovered by a simple filtration of the reaction solution and used for at least 10 consecutive trials without any decreases in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.

A highly efficient heterogeneous cross-dehydrogenative coupling (CDC) of tertiary amines with nitroalkanes and various unmodified ketones was achieved by using a magnetic nanoparticle-immobilized bipy–gold(III) complex as catalyst and air as the sole oxidant to afford the corresponding C–C coupling products in good to excellent yields under mild reaction conditions. The new heterogeneous gold catalyst can easily be separated from the reaction mixture by applying an external magnet and can be recycled at least ten times without a significant loss of activity.

The heterogeneous decarboxylative cross-coupling reaction of potassium polyfluorobenzoates with aryl iodides and bromides was achieved in diglyme or DMAc at 130 or 160 °C in the presence of 10–20 mol% of a 1,10-phenanthroline-functionalized MCM-41-immobilized copper(I) complex, [MCM-41-Phen-CuI], yielding a variety of polyfluorobiaryls in good to excellent yields. This heterogeneous copper(I) complex could easily be prepared via a simple procedure from commercially readily available and inexpensive reagents, exhibited the same catalytic activity as the homogeneous CuI/Phen system, and was recovered by filtration of the reaction solution and recycled at least 8 times without significant loss of catalytic activity.

The direct reductive amination of aldehydes and ketones has been achieved in dichloromethane at room temperature by using a magnetic nanoparticle-supported phosphine gold(I) complex [Fe3O4@SiO2-P–AuCl] as the catalyst and ethyl Hantzsch ester as the hydrogen source, yielding a variety of secondary amines in excellent yields under neutral conditions. The new heterogeneous gold catalyst can be prepared by a simple procedure from commercially readily available reagents and can easily be separated from the reaction mixture by applying an external magnet and recycled at least 10 times without any loss of activity.

A highly efficient heterogeneous three-component coupling of tetrahydroisoquinolines, aldehydes and 1-alkynes was achieved in toluene at 70 °C in the presence of a 3-(2-aminoethylamino)propyl-functionalized MCM-41-supported copper(I) complex [MCM-41-2N–CuI], yielding a variety of C1-alkynylated tetrahydroisoquinolines (endo-yne-THIQs) in good to excellent yields with high regioselectivity. This heterogeneous copper catalyst can be easily prepared by a simple two-step procedure from commercially available and inexpensive reagents, and recovered by a simple filtration and reused for at least 10 times without any decrease in activity.

A heterogeneous Chan–Lam coupling reaction between sulfonyl azides and arylboronic acids was achieved in MeOH at room temperature in the presence of 10 mol% of an L-proline-functionalized MCM-41-immobilized copper(I) complex [MCM-41–L-proline–CuCl] under air, yielding a variety of N-arylsulfonamides in excellent yields. The new heterogeneous copper complex can be prepared from commercially readily available and inexpensive reagents, and recovered by simple filtration of the reaction solution and recycled at least 8 times without any decreases in activity.

Oxidative α-cyanation of tertiary amines with trimethylsilyl cyanide was achieved by using a magnetic nanoparticles-supported gold(III)-bipy complex as catalyst to afford the corresponding α-aminonitriles in good to excellent yields in the presence of tert-butyl hydroperoxide under acid-free conditions. The new heterogeneous gold catalyst can easily be separated from the reaction mixture by using an external magnet and can be recycled for at least 10 times without any loss of activity.

The first phosphine-free heterogeneous atom-efficient cross-coupling of aryl iodides with triarylbismuths was achieved in NMP using K2CO3 as base at 110 °C in the presence of 2 mol % of an MCM-41-immobilized palladium(II)-Schiff base complex [MCM-41-N,N-Pd(OAc)2], yielding a variety of unsymmetrical biaryls in good to excellent yields. This new heterogeneous palladium catalyst exhibits high catalytic activity and can be recovered by a simple filtration of the reaction solution and recycled for at least 10 consecutive trials without any decreases in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.

The heterogeneous Chan-Lam coupling reaction between thiols and arylboronic acids was achieved in EtOH at room temperature in the presence of 5 mol % of MCM-41-immobilized 1,10-phenanthroline-copper(II) complex [MCM-41-1,10-Phen-CuSO4] with n-Bu4NOH (40% aq) as base under O2 atmosphere, yielding a variety of unsymmetrical diaryl sulfides in good to excellent yields under mild and green conditions. The new heterogeneous copper complex can easily be prepared by a simple procedure from commercially readily available and inexpensive reagents, and recovered by a simple filtration of the reaction solution and recycled for at least eight times without significant loss of catalytic activity.

A novel and highly efficient heterogeneous palladium-catalyzed carbonylative cross-coupling of aryl iodides with triarylbismuths has been developed that proceeds smoothly at atmospheric CO pressure and provides a general and powerful tool for the preparation of various valuable biaryl ketones with high atom economy, good to excellent yield, and recyclability of the catalyst. The reaction is the first example of Pd-catalyzed carbonylative cross-coupling for the construction of biaryl ketones using triarylbismuths as substrates.

A highly efficient MCM-41-immobilized bipyridine copper(I) complex [MCM-41-bpy-CuI] was prepared from 4,4′-bis[3-(triethoxysilyl)propylaminomethyl]-2,2′-bipyridine via immobilization on the mesoporous material MCM-41, followed by reaction with CuI. In the presence of 5 mol% MCM-41-bpy-CuI, the cross-coupling reaction of organoboronic acids with diaryl diselenides proceeded smoothly in DMSO/H2O (2/1) at 110 °C under air to afford a variety of diorganyl selenides in good to excellent yields. This heterogeneous copper catalyst can be recovered and recycled by a simple filtration of the reaction solution and used for at least 10 consecutive trials without any decrease in activity.

[RuCl2(p-cymene)]2 in a mixture of poly(ethylene glycol) (PEG-400) and water is shown to be an extremely efficient catalyst for the cross-dehydrogenative C–H bond alkenylation reaction between benzoic acids and alkenes. The reaction could be conducted at 80 °C using Cu(OAc)2·H2O as oxidant, yielding a variety of phthalide derivatives in good to excellent yields. More importantly, both [RuCl2(p-cymene)]2 and Cu(OAc)2 in the PEG-400/H2O system could be easily recycled and reused six times without any loss of catalytic activity.

A heterogeneous copper(I)-catalyzed aerobic oxidation of primary benzylic and allylic alcohols to aldehydes was achieved under air in EtOH at 50 °C in the presence of 5 mol % of MCM-41-immobilized bipyridine copper(I) complex [MCM-41-bpy-CuI] and 5 mol % of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) using aqueous ammonia as base, yielding a variety of aromatic and α,β-unsaturated aldehydes in good to excellent yields. This heterogeneous copper catalyst can be easily recovered by a simple filtration of reaction solution and reused for at least 10 consecutive trials without any decreases in activity. The use of recyclable heterogeneous copper catalyst and green reagents, such as air as oxidant and ethanol as solvent, made the system attractive for environmentally sustainable processes.

PdCl2(PPh3)2 in a mixture of water and poly(ethylene glycol) (PEG-2000) is shown to be an extremely active catalyst for the carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes. The reaction can be conducted under an atmospheric pressure of carbon monoxide at 25 °C with Et3N as a base, yielding a variety of alkynyl ketones in good to excellent yields. Application of this synthetic method to prepare flavones from o-iodophenol and terminal alkynes was also achieved. The isolation of the products is readily achieved by extraction with diethyl ether, and the PdCl2(PPh3)2/PEG-2000/H2O system can be easily recycled and reused six times without any loss of catalytic activity.

An efficient route to 5H-benzo[d]imidazo[5,1-b][1,3]thiazines has been developed using the copper(I)-catalyzed tandem reaction of o-alkynylphenyl isothiocyanates with isocyanides in THF with Cs2CO3 as base. The present tandem process allows the assembly of a variety of 5H-benzo[d]imidazo[5,1-b][1,3]thiazines in good to excellent yields.

Trimethylsilylacetylene undergoes clean cis-addition to alkynyl sulfones or esters 1 in the presence of catalytic palladium acetate and tri(2,6-dimethoxyphenyl)phosphine to give (E)-1-sulfonyl (or ethoxycarbonyl)-4-trimethylsilyl-substituted 1,3-enyne 2 in excellent yields. The cross-coupling reaction of (E)-1-sulfonyl (or ethoxycarbonyl)-4-trimethylsilyl-substituted 1,3-enyne 2 with (E)-alkenyl iodides 3 in the presence of Pd(PPh3)4 and tris(diethylamino)sulfonium trimethyldifluorosilicate (TASF) affords stereoselectively (1E,5E)-1-sulfonyl (or ethoxycarbonyl)-substituted 1,5-dien-3-ynes 4 in good yields.

An efficient route to indolyl imidazole derivatives has been developed through a base-promoted tandem reaction of N-[2-(1-alkynyl)phenyl]carbodiimides with isocyanides in DMSO at 40 °C. The present tandem process allows the assembly of a variety of indolyl imidazole derivatives in moderate to good yields.

The phosphine-free heterogeneous coupling of acyl chlorides with terminal alkynes was achieved in triethylamine at 50 °C in the presence of a 0.2 mol% 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium complex [MCM-41-2N-Pd(OAc)2], yielding a variety of ynones in good to excellent yields. This novel heterogeneous palladium catalyst can be conveniently prepared from commercially available and cheap reagents and recycled by a simple filtration of the reaction solution, and used for at least 10 consecutive trials without any decrease in activity. Our system not only avoids the use of phosphine ligands, but also solves the basic problem of palladium catalyst recovery and reuse.

Palladium-catalyzed cross-coupling reactions of phenyl tributylstannyl selenide with aryl and alkyl halides can proceed smoothly in room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), to give the corresponding diorganyl selenides in good to high yields. The coupling reaction run in [bmim][PF6] has the advantages of rate acceleration and increase of yield in contrast to the reaction run in toluene. Our system not only avoids the use of easily volatile toluene as a solvent but also solves the basic problem of palladium catalyst reuse.

The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 °C in the presence of 0.01 mol% of thioether-functionalized MCM-41 anchored rhodium complex, affording the corresponding addition products in 68–91% yields. This supported rhodium complex can be reused several times without noticeable loss of activity. Our system not only solves the basic problems of catalyst separation and recovery, but also avoids the use of phosphine ligands.

A highly efficient heterogeneous cross-dehydrogenative coupling (CDC) of tertiary amines with nitroalkanes and various unmodified ketones was achieved by using a magnetic nanoparticle-immobilized bipy–gold(III) complex as catalyst and air as the sole oxidant to afford the corresponding C–C coupling products in good to excellent yields under mild reaction conditions. The new heterogeneous gold catalyst can easily be separated from the reaction mixture by applying an external magnet and can be recycled at least ten times without a significant loss of activity.

The direct reductive amination of aldehydes and ketones has been achieved in dichloromethane at room temperature by using a magnetic nanoparticle-supported phosphine gold(I) complex [Fe3O4@SiO2-P–AuCl] as the catalyst and ethyl Hantzsch ester as the hydrogen source, yielding a variety of secondary amines in excellent yields under neutral conditions. The new heterogeneous gold catalyst can be prepared by a simple procedure from commercially readily available reagents and can easily be separated from the reaction mixture by applying an external magnet and recycled at least 10 times without any loss of activity.

An efficient route to 5H-benzo[d]imidazo[5,1-b][1,3]thiazines has been developed using the copper(I)-catalyzed tandem reaction of o-alkynylphenyl isothiocyanates with isocyanides in THF with Cs2CO3 as base. The present tandem process allows the assembly of a variety of 5H-benzo[d]imidazo[5,1-b][1,3]thiazines in good to excellent yields.

A highly efficient heterogeneous three-component coupling of tetrahydroisoquinolines, aldehydes and 1-alkynes was achieved in toluene at 70 °C in the presence of a 3-(2-aminoethylamino)propyl-functionalized MCM-41-supported copper(I) complex [MCM-41-2N–CuI], yielding a variety of C1-alkynylated tetrahydroisoquinolines (endo-yne-THIQs) in good to excellent yields with high regioselectivity. This heterogeneous copper catalyst can be easily prepared by a simple two-step procedure from commercially available and inexpensive reagents, and recovered by a simple filtration and reused for at least 10 times without any decrease in activity.