A New Class of Amide Ligands Enable Cu‐Catalyzed Coupling of Sodium Methanesulfinate with (Hetero)aryl Chlorides

((2S ,4R )‐4‐Hydroxy‐N ‐(2‐methylnaphthalen‐1‐yl)pyrrolidine‐2‐carboxamide (HMNPC), an amide derived from 4‐hydroxy‐L ‐proline and 2‐methyl naphthalen‐1‐amine, is a powerful ligand for Cu‐catalyzed coupling of (hetero)aryl halides with sulfinic acid salts, allowing for first time the metal‐catalyzed coupling of (hetero)aryl chlorides and NaSO₂Me. A considerable number of (hetero)aryl chlorides worked well, providing the pharmaceutically important (hetero)aryl methylsulfones in good to excellent yields.     

Nickel‐Catalyzed Cross‐Coupling of Sulfonamides With (Hetero)aryl Chlorides

The development of Ni‐catalyzed C?N cross‐couplings of sulfonamides with (hetero)aryl chlorides is reported. These transformations, which were previously achievable only with Pd catalysis, are enabled by use of air‐stable ( L )NiCl(o‐tol) pre‐catalysts (L= PhPAd‐DalPhos and PAd2‐DalPhos ), without photocatalysis. The collective scope of (pseudo)halide electrophiles (X=Cl, Br, I, OTs, and OC(O)NEt₂) demonstrated herein is unprecedented for any reported catalyst system for sulfonamide C?N cross‐coupling (Pd, Cu, Ni, or other). Preliminary competition experiments and relevant coordination chemistry studies are also presented.     

Nickel-Catalyzed Cross-Coupling of Sulfonamides With (Hetero)aryl Chlorides

The development of Ni-catalyzed C−N cross-couplings of sulfonamides with (hetero)aryl chlorides is reported. These transformations, which were previously achievable only with Pd catalysis, are enabled by use of air-stable ( L )NiCl(o-tol) pre-catalysts (L= PhPAd-DalPhos and PAd2-DalPhos ), without photocatalysis. The collective scope of (pseudo)halide electrophiles (X=Cl, Br, I, OTs, and OC(O)NEt₂) demonstrated herein is unprecedented for any reported catalyst system for sulfonamide C−N cross-coupling (Pd, Cu, Ni, or other). Preliminary competition experiments and relevant coordination chemistry studies are also presented.     

A General Palladium‐Catalyzed Hiyama Cross‐Coupling Reaction of Aryl and Heteroaryl Chlorides

A general palladium‐catalyzed Hiyama cross‐coupling reaction of aryl and heteroaryl chlorides with aryl and heteroaryl trialkoxysilanes by a Pd(OAc)₂/ L2 catalytic system is presented. A newly developed water addition protocol can dramatically improve the product yields. The conjugation of the Pd/ L2 system and the water addition protocol can efficiently catalyze a broad range of electron‐rich, ‐neutral, ‐deficient, and sterically hindered aryl chlorides and heteroaryl chlorides with excellent yields within three hours and the catalyst loading can be down to 0.05 mol % Pd for the first time. Hiyama coupling of heteroaryl chlorides with heteroaryl silanes is also reported for the first time. The reaction can be easily scaled up 200 times (100 mmol) without any degasification and purification of reactants; this facilitates the practical application in routine synthesis.     

Mild Cobalt‐Catalyzed Negishi Cross‐Couplings of (Hetero)arylzinc Reagents with (Hetero)aryl Halides

A catalytic system consisting of CoCl₂ ? 2 LiCl (5 mol %) and HCO₂Na (50 mol %) enables the cross‐coupling of various N‐heterocyclic chlorides and bromides as well as aromatic halogenated ketones with various electron‐rich and ‐poor arylzinc reagents. The reactions reached full conversion within a few hours at 25 °C.     

Nickel‐Catalyzed N‐Arylation of Primary Amides and Lactams with Activated (Hetero)aryl Electrophiles

The first nickel‐catalyzed N‐arylation of amides with (hetero)aryl (pseudo)halides is reported, enabled by use of the air‐stable pre‐catalyst (PAd‐DalPhos)Ni(o‐tolyl)Cl ( C1 ). A range of structurally diverse primary amides and lactams were cross‐coupled successfully with activated (hetero)aryl chloride, bromide, triflate, tosylate, mesylate, and sulfamate electrophiles.     

Nickel‐Catalyzed Cross‐Coupling of Organolithium Reagents with (Hetero)Aryl Electrophiles

Nickel‐catalyzed selective cross‐coupling of aromatic electrophiles (bromides, chlorides, fluorides and methyl ethers) with organolithium reagents is presented. The use of a commercially available nickel N‐heterocyclic carbene (NHC) complex allows the reaction with a variety of (hetero)aryllithium compounds, including those prepared via metal‐halogen exchange or direct metallation, whereas a commercially available electron‐rich nickel‐bisphosphine complex smoothly converts alkyllithium species into the corresponding coupled product. These reactions proceed rapidly (1 h) under mild conditions (room temperature) while avoiding the undesired formation of reduced or homocoupled products.     

PhPAd‐DalPhos: Ligand‐Enabled,Nickel‐Catalyzed Cross‐Coupling of (Hetero)aryl Electrophiles with Bulky Primary Alkylamines

The base metal‐catalyzed C?N cross‐coupling of bulky α,α,α‐trisubstituted primary alkylamines with (hetero)aryl electrophiles represents a challenging and under‐developed class of transformations that is of significant potential utility, including in the synthesis of lipophilic active pharmaceutical ingredients. Herein, we report that a new, air‐stable Ni(II) pre‐catalyst incorporating the optimized ancillary ligand PhPAd‐DalPhos enables such transformations of (hetero)aryl chloride, bromide, and tosylate electrophiles to be carried out for the first time with substrate scope rivalling that achieved using state‐of‐the‐art Pd catalysts, including room temperature cross‐couplings of (hetero)aryl chlorides that are unprecedented for any catalyst (Pd, Ni, or other).     

Microwave-Accelerated Selective Acylation of (Hydroxyalkyl)phenols Using Acid Chlorides

Highly selective acylation of the alcoholic hydroxy group can be achieved with (hydroxyalkyl)phenols carrying both alcoholic and phenolic hydroxyls by the use of the most common acylating agents, acid chlorides, under microwave irradiation.     

Chemo‐selective copper‐catalyzed C‐O coupling reactions of phenols with aryl/vinyl halides using enaminone as efficient ligand

The copper‐catalyzed Ullmann C‐O coupling reactions between phenols and aryl/vinyl halides have been efficiently performed by employing (E)‐3‐(dimethylamino)‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐one, an easily available enaminone, as ligand. This new ligand is advantageous for its easy availability, broad applicability and good efficiency. Copyright © 2012 John Wiley & Sons, Ltd.     

Ligand-Facilitated Reductive Coupling of Benzyl Chlorides with Aryl Chlorides Catalyzed by Well-Defined Heteroleptic Ni (II)-NHC Complexes

Novel heteroleptic Ni (II) complexes bearing a highly hindered yet flexible IPr^* ligand, Ni (IPr^*)(PPh₃)Br₂ ( 1 ) and Ni (IPr^*)(PCy₃)Br₂ ( 2 ) (IPr^* = 1,3-bis(2,6-bis (diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene), were easily prepared in 78% and 89% yield, respectively. Both were characterized by elemental analysis and NMR spectroscopy, and 1 was subjected to X-ray crystallography. Compared with 2 and its analogue bearing a less sterically demanding IPr ligand (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), complex 1 exhibited superior catalytic activity in the magnesium-mediated reductive coupling of benzyl chlorides with aryl chlorides, featuring outstanding tolerance of both coupling partners with steric demand. This study discloses a ligand-facilitated reductive coupling of benzyl chlorides with aryl chlorides, which provides a new and practical synthetic tool for the synthesis of diarylmethanes.     

Trifluoromethoxylation Reactions of (Hetero) arenes,Olefinic Systems and Aliphatic Saturated Substrates

Direct fluoroalkoxylation reactions of (hetero)arenes, carbon-carbon multiple bonds, and substitution reactions at Csp³ carbon centers by CF₃O, CHF₂O, and (CF₃)₂CFO groups are discussed. Emphasis on thermal radical, electron transfer, photocatalytic, electrochemical and redox-neutral radical methods are placed to accomplish fluoroalkoxylation reactions. All these methods employ either radical fluoroalkoxylating reagents or some nucleophilic trifluoromethoxylating sources of CF₃O. A summary of all these methods is provided in Table 2.     

Nickel‐Catalyzed Difluoroalkylation of (Hetero)Arylborons with Unactivated 1‐Bromo‐1,1‐difluoroalkanes

A nickel‐catalyzed cross‐coupling between (hetero)arylborons and unactivated 1‐bromo‐1,1‐difluoroalkanes has been developed. The use of two ligands (a bidentate bipyridine‐based ligand, 4,4′‐ditBu‐bpy, and a monodentate pyridine‐based ligand, DMAP) offers a highly efficient nickel‐based catalytic system to prepare difluoroalkylated arenes which have important applications in medicinal chemistry.     

Development of a palladium-catalyzed decarboxylative cross-coupling of (2-azaaryl)carboxylates with aryl halides

A catalytic method for the decarboxylative coupling of 2-(azaaryl)carboxylates with aryl halides is described. The decarboxylative cross-coupling presented is mediated by a system catalytic in both palladium and copper without requiring stoichiometric amounts of organometallic reagents or organoboronic acids. This method circumvents additional synthetic steps required to prepare 2-azaaryl organometallics and organoborates as nucleophilic coupling partners, which are prone to protodemetallation and protodeborylation and produce potentially toxic byproducts.     

应用腙作为配体的铜催化二芳醚合成反应

一种简单易得的腙,2-吡啶醛 1-苯基腙 （1）,能够作为有效配体,极大地促进碘化铜催化的芳基溴与酚的C–O偶联反应。该偶联反应条件温和（二氧六环为溶剂、磷酸钾为碱、90–100 0C 的反应温度）,适用于各种芳基溴（电中性、贫电子和富电子）和酚（电中性和富电子）的底物,能够相容一些碱敏感官能团如酯基、醛基和羰基等。     

二氧化硅负载胂钯(0)配合物催化酰氯和芳基碘与四苯硼化钠的苯基化反应

氯丙基三乙氧基硅烷依次与气相法二氧化硅、二苯胂钾、氯化钯作用, 再用水合肼还原, 合成了二氧化硅负载的胂钯(0)配合物. 该配合物是酰氯及芳基碘化物与四苯硼化钠苯基化反应的有效催化剂, 为苯基酮及不对称联苯的合成提供了简便且实用的新方法.     

Amide Synthesis by Nickel/Photoredox‐Catalyzed Direct Carbamoylation of (Hetero)Aryl Bromides

Herein, we report a one‐electron strategy for catalytic amide synthesis that enables the direct carbamoylation of (hetero)aryl bromides. This radical cross‐coupling approach, which is based on the combination of nickel and photoredox catalysis, proceeds at ambient temperature and uses readily available dihydropyridines as precursors of carbamoyl radicals. The method's mild reaction conditions make it tolerant of sensitive‐functional‐group‐containing substrates and allow the installation of an amide scaffold within biologically relevant heterocycles. In addition, we installed amide functionalities bearing electron‐poor and sterically hindered amine moieties, which would be difficult to prepare with classical dehydrative condensation methods.     

A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base

Aryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me₂S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2050–2058