Synthesis of 9Z-9-substituted retinoic acids by palladium catalyzed coupling reaction of a vinyl triflate with alkenyl stannanes

Palladium catalyzed cross coupling reactions of a vinyl triflate intermediate and various alkenyl stannanes afforded trisubstituted Z-olefins stereoselectively in high yields. These olefins were then converted to the corresponding 9Z-retinoic acids via Horner-Emmons reaction and subsequent basic hydrolysis in excellent yields.     

Synthesis of O-aminodihydroartemisinin via TMS triflate catalyzed C-O coupling reaction

O-Aminodihydroartemisinin was synthesized for the first time via TMS triflate catalyzed coupling reaction of O-acetylartemisinin. The reaction proceeds with high yield without losing the endoperoxide of the artemisinin backbone. The new coupling reaction was employed to prepare artemisinin O-glycosides with improved water solubility. O-Aminodihydroartemisinin reacts readily with benzaldehyde to give the corresponding oxime derivative, demonstrating the potential of this compound for the preparation of various artemisinin conjugates.     

Synthesis of terbinafine. A palladium catalyzed vinyl iodide-ethynylstannane coupling

Hydrozirconation of propargylamine (2) followed by cleavage with iodine leads to the formation of (E)-vinyl iodide (4). Palladium catalyzed coupling of 4 and 3,3-dimethylbutynylstannane results in the formation of Terbinafine (1a).     

Heterogeneous copper-free Sonogashira coupling reaction catalyzed by a reusable palladium Schiff base complex in water

Heterogeneous Sonogashira coupling of terminal alkynes with aryl halides was studied over a polymer-supported macrocyclic Schiff base palladium complex. The cross-coupling reaction proceeded smoothly by adding a piperidine in water medium. The catalyst exhibited effective catalytic activities to afford the corresponding products in good to excellent yields under copper-free conditions. Furthermore, the catalyst could be easily recovered and reused for several times without a significant loss of its activity.     

Cross-linked polymer supported palladium catalyzed carbonylative Sonogashira coupling reaction in water

A cross-linked polymer-supported ionic liquid immobilized palladium catalyst, which is prepared by reaction of the Pd(OAc)₂ with copolymer of 3-butyl-1-vinylimidazolium iodide and divinylbenzene, was well characterized and employed as an effective heterogeneous catalyst for carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes in water, affording the corresponding α,β-alkynyl ketones in good to excellent yields. The catalytic system not only solves the basic problem of homogeneous palladium catalyst recovery and reuse but also avoids the use of toxic phosphine ligands. The stability of supported palladium was also discussed.     

Sonogashira coupling of aryl halides catalyzed by palladium on charcoal

With the proper choice of solvent, palladium on charcoal acts as an efficient catalyst in the Sonogashira cross-coupling reaction of aryl bromides. The catalytically active species in the process is probably palladium, which leaches into the solution but returns onto the surface of the charcoal at the end of the reaction.     

Heck reaction catalyzed by a recyclable palladium supported on shell powder

A novel palladium catalyst supported on shell powder has been prepared, and its application to the Heck reaction of aryl iodides with olefins has been reported. The results showed that the novel catalyst had extremely high activities for the reactions with the average yield over 90%. Also, this catalyst showed excellent stability in Heck reactions, being reused three times. The catalyst was characterized by X‐ray powder diffraction and field‐emission scanned electron microscopy images, and the energy dispersive X‐ray analyzer. Copyright © 2010 John Wiley & Sons, Ltd.     

Silver triflate catalyzed reaction of 2-alkynylbenzaldoxime with aryne

A novel and unexpected reaction of 2-alkynylbenzaldoxime with aryne in the presence of silver triflate (10 mol %) under mild conditions is discovered. This reaction proceeds through 6-endo-cyclization, [3 + 2] cycloaddition, and rearrangement, leading to 2-oxa-6-aza-bicyclo[3.2.2]nona-6,8-diene derivatives in moderate to good yields.     

First example of a palladium catalyzed coupling reaction between cationic porphyrins and alkynyls in aqueous medium

The first example of the palladium catalyzed (Sonogashira) carbon-carbon coupling reaction in aqueous medium between 5,10,15-tri-(4-N-methylpyridyl)-20-(4-bromophenyl)-porphyrin and a variety of terminal alkynyls is reported.     

Carbon-carbon and carbon-nitrogen coupling reactions catalyzed by palladium nanoparticles derived from a palladium substituted Keggin-type polyoxometalate

Palladium 15-20 nm particles stabilized by a Keggin-type polyoxometalate were prepared by reduction of K(5)PPdW(11)O(39) with H(2). The nanoparticles were shown to be effective catalysts for Suzuki-, Heck-, and Stille-type carbon-carbon coupling and carbon-nitrogen coupling reactions of bromoarenes in aqueous media. Chloroarenes were also reactive in reaction media without solvent. [reaction: see text]     

A highly efficient asymmetric Suzuki-Miyaura coupling reaction catalyzed by cationic chiral palladium(ii) complexes

Cationic chiral palladium(ii) complexes are shown to catalyze the asymmetric coupling reaction of aryl boronates and aryl halides within a short period of time in good yield and enantioselectivity.     

钯配合物催化的芳基-芳基不对称偶联反应

本文以三种匀性膦作配体制成了零价钯配合物, 并分虽试验了由它们催化苯酚得到的α-溴-β-苄氧基萘和进一步衍生而得的格氏试剂的偶联反应, 制成了β'β'-二苄氧基-α', α'-联萘.     

钯或镍催化的有机镁及有机锌的不对称交叉偶联反应

综述了钯或镍的手性配合物催化的有机金属试剂与芳基及烯基卤化物的不对称交叉偶联反应,着重介绍了手性配体的发展及其对反应产物ee值的影响。对一些已研究得较清楚的反应的可能立体识别机理也作了介绍。     

Olefinic substitution reaction catalyzed by sulfur-containing polymeric palladium complexes

Silica-supported sulfur-containing polymeric palladium complexes were synthesized by the coordination of sulfur-containing polymeric ligands with palladium acetate or palladium chloride. The activated alkenes were reacted selectively with iodobenzene in the presence of tertiary amines and polymeric palladium complexes containing sulfur to give phenyl-substituted derivatives. High yields can be obtained under appropriate conditions with a low catalyst concentration. The sulfur-containing polymeric palladium complexes showed higher activities and better selectivities and stabilities than the corresponding phosphine-containing systems.     

A route to conformationally restricted antioestrogens by coupling of a vinyl triflate with an aryl zinc chloride

Palladium complex catalysed coupling of a benzocycloheptenyl triflate with aryl zinc chlorides gives an efficient approach to the synthesis of conformationally restricted antioestrogens.     

A Sakurai-Prins-Ritter reaction sequence for the diastereoselective synthesis of 4-amidotetrahydropyrans catalyzed by bismuth triflate

The synthesis of 4-amidotetrahydropyrans has been achieved by a single-step Sakurai-Prins-Ritter reaction sequence in a domino fashion by the reaction of an aldehyde and allyltrimethylsilane in acetonitrile using Bi(OTf)₃ as catalyst. The present synthesis is highly efficient and diastereoselective.     

Copper- and ligand-free Sonogashira reaction catalyzed by palladium in microemulsion

An oil-in-water microemulsion containing PdCl2 and NaOH can be used as an effective catalyst system for rapid copper- and ligand-free Sonogashira reaction of aryl halides and phenylacetylene. Excellent yield of the Sonogashira reaction catalyzed by 0.5 mol% palladium could be achieved within 5 min. The types of base have an intense influence on the reaction. The reaction rate was increased with increased aqueous content in the microemulsions, and dispersed palladium nanoparticles can be in situ formed without other reductants.     

Phosphine-free palladium catalyzed Mizoroki-Heck reaction using hydrazone as a ligand

Glyoxal bishydrazones 1 and pyridyl-hydrazone 2b were prepared and examined as a ligand for the Mizoroki-Heck cross-coupling reaction of aryl halides and olefin. We found that PdCl2(MeCN)2/hydrazone ligand 1e was a phosphine-free efficient catalyst system for a variety of substrates to produce the Mizoroki-Heck coupling products in good yields.