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A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp2)-O electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-electrophile coupling reactions.

Herein, we first present a nickel-catalyzed arylation and alkenylation of tert-cyclobutanols with aryl/alkenyl triflates via a C-C bond cleavage. An array of γ-substituted ketones was obtained in moderate-to-good yields, thus featuring earth-abundant nick

Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-electrophile arylation reaction of benzyl alcohols with (hetero)aryl electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl electrophiles.

Metal-catalysed ortho-directed C-H functionalization usually faces selectivity issues in the competition between mono- and disubstitution processes. We report herein the ruthenium-catalysed N-directed C-H monoarylation of arylpyrazoles with a selectivity

A mild and practical Barbier–Negishi coupling of secondary alkyl bromides with aryl and alkenyl triflates and nonaflates has been developed. This challenging reaction was enabled by the use of a very bulky imidazole-based phosphine ligand, which resulted in good yields as well as good chemo- and site selectivities for a broad range of substrates at room temperature and under non-aqueous conditions. This reaction was extended to primary alkyl bromides by using an analogous pyrazole-based ligand.

N-Aryl-protecting groups were introduced in glucosamines to achieve β-selective glycosylation. Various N-aryl aminosugars were synthesized via Buchwald–Hartwig reaction. Glycosylation using glycosyl trichloroacetimidates of N-aryl aminosugars smoothly proceeded in the presence of trimethylsilyl trifluoromethanesulfonate. Use of a glycosyl donor comprising an electron-donating 2,4-dimethoxyphenyl (DMP) group led to the glycosylation proceeding with high β selectivity. This stereoselectivity seemed to be derived from the formation of an aziridine intermediate. The DMP-protecting group can be removed immediately by using ammonium hexanitratocerate (IV).

A low-energy, high-selectivity approach to the catalytic hydrodeoxygenation of phenols is reported using batch or continuous flow methods to react 3 equiv of phenol with cyanuric chloride then hydrogenolyzing the triarylcyanurate intermediate to give 3 equiv of deoxo aromatic. The use of cyanuric chloride compares favorably with existing activation methods, showing improved scalability, atom efficiency, and economics. The scope of both the activation and hydrogenolysis stages are explored using lignin-related phenols. Initial development has identified that continuous stir tank reactors (CSTRs) enable a multiphasic process for converting guaiacol to anisole and at steady state overcome the catalyst deactivation issues observed in batch, seemingly caused by the cyanurate byproduct. Green chemistry aspects and the potential for industrial adoption are discussed.

A novel method for Pd-catalyzed triflination of aryl and heteroaryl triflates using NaSO2CF3 as the nucleophile is described. The combination of Pd2(dba)3 and RockPhos formed the most effective catalyst. A broad range of functional groups and heteroaromatic compounds were tolerated under the neutral reaction conditions. The order of reactivity ArOTf ≥ ArCl ≥ ArBr is consistent with transmetalation being a slow step of the reaction.

In intermolecular Heck reactions of styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the α position has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 α selectivity. The key to our success is a new ferrocene 1,1′-bisphosphane (dnpf) that carries 1-naphthyl groups. Our mechanistic studies revealed that the high α selectivity is partly attributable to the steric effect of dnpf. The rigid and bulky 1-naphthyl groups of dnpf sterically disfavor β insertion. What the Heck! In intermolecular Heck reactions, insertion at the β position of aromatic olefins is very common, but reversal of the selectivity for selective α insertion has been a longstanding problem. A general method to couple aryl and vinyl triflates with aromatic olefins in >20:1 α selectivity is presented. The key to this successful approach is a new ferrocene bisphosphane with naphthyl groups on the phosphorus atom (see scheme; OTf=triflate). Copyright

Bisphosphine oxides formed highly active asymmetric Heck catalysts, which were applied in asymmetric synthesis of pharmacologically active azacycles. Olefin insertion proceeded via cis pathways, different from P,N-ligands.

The invention is directed to inhibitors of cystathionine beta synthase which, among other biochemical effects, allow reduction of the neurotoxic overproduction of endogenous hydrogen sulphide. These compounds and pharmaceutical compositions containing them are useful for the prevention and treatment of cognitive disorders such as cognitive disorders in Down syndrome. The invention also relates to methods for preventing or treating cognitive disorders including cognitive disorders in Down Syndrome.

In Heck reactions of cyclic olefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclic olefins of various ring size worked well. The desired isomers were produced by palladium-hydride-catalyzed isomerization of the initial products. Thus, a specific catalyst must be used so that it can perform two jobs under one set of reaction conditions. Copyright

The disclosure provides new and improved methods for the Pd-catalyzed asymmetric α-arylation of ester compounds, which produce the corresponding α-aryl moiety in high enantioselectivity (generally >90% ee). The present methods utilize a palladium catalyst supported by new (R)-H8-BINOL-derived monophosphine ligands. The method is applicable to a wide variety of aryl triflate substrates having variations in both electronic and steric properties. These aryl triflate substrates react with various α-alkyl (Z)- and/or (E)-0-trimethylsilyl ketene acetals in the presence of a Pd catalyst, (R)-H8-BINOL-derived monophosphine ligand, and a mild activator, for example, LiOAC, to provide the asymmetric α-arylation of ester compounds in high ee.

New ligand for old reaction: The title reaction of aryltriflates with aliphatic olefins leads to substitution at the internal position with high selectivity. The ratio of the desired isomer (shown in the scheme) to the sum of all other isomers is generall

An efficient Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates as arylation reagents by C-O bond cleavage of aryl triflates was developed. With only 2 mol % of Pd(OAc)2 as catalyst and XPhos as ligand, the reaction proceeded well for a range of substrates.

In transition-metal catalyzed, asymmetric α-arylation of carbonyl compounds, formation of tertiary centers with high enantioselectivity is a longstanding problem, due to easy enolization of the monoarylation products. Herein, we report such examples using a palladium catalyst supported by a new, (R)-H8-BINOL-derived monophosphine. Silyl ketene acetals, together with a weakly basic activator, were used as equivalents of ester anions, and they reacted smoothly with aryl triflates in excellent enantiomeric excess (ee). The usefulness of the reaction was demonstrated in a gram-scale synthesis of (S)-Naproxen in 92% ee.

A one-pot synthetic procedure for 2,2′-disubstituted biaryls was developed via a Suzuki cross-coupling reaction of aryl triflates in a biphasic solvent system. The effects of various bases and solvents were investigated. Results showed that the Na2/

Pentavalent aryl and heteroaryl bis(catechol) silicates undergo palladium-catalyzed cross-coupling with aryl and heteroaryl triflates in the presence of a fluoride source in excellent yields. These solid, air-stable bis(catechol) silicates are prepared from a high-yielding displacement reaction between catechol and an aryl siloxane in the presence of an amine base. The cross-coupling reaction is tolerant of a wide range of electron-donating and electron-withdrawing groups. Several examples of di-ortho-substituted triflates are successfully coupled with these reagents.

Catalytic user-friendly approach to the syntheses of various functionalized aromatic phosphines from their corresponding substituted aryl triflates and triarylphosphines was accomplished. This method is carried out in neutral media and compatible with man

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Arylzincates bearing a leaving group at the ortho, meta, and para positions were generated by iodine/zinc exchange reaction of the corresponding iodoaryl sulfonates with Bu3ZnLi, and their reactivity was investigated via product analysis after hydrolysis and treatment with iodine. Zincates derived from o-iodophenyl triflates and tosylate underwent homologation reaction to give o-butylphenylzinc species. o-Benzyne as an intermediate of the reaction was demonstrated by the lack of regioselectivity for trisubstituted zincates. Zincates derived from m-iodophenyl triflates also underwent homologation leading to m-butylphenylzinc species. Similar product ratios observed in the reactions of regioisomeric trisubstituted iodophenyl triflates as well as the formation of radical reaction byproducts suggested the involvement of m-benzyne intermediate. p-(Trifluoromethane-sulfonyloxy)phenylzincate was thermally stable at room temperature; generation of p-benzyne was not observed.

Aryl triflates were prepared under mild conditions using 4-nitrophenyl triflate (1) as a stable, crystalline triflating agent.

The further evolution of the imidazole-5-acrylic acid series of nonpeptide angiotensin II receptor antagonists is detailed (for Part 1, see: J.Med.Chem. 1992, 35, 3858).Modifications of the N-benzyl ring substitution were undertaken in an effort to mimic the Tyr4 residue of angiotensin II.Introduction of a p-carboxylic acid on the N-benzyl ring resulted in the discovery of compounds with nanomolar affinity for the receptor and good oral activity.SAR studies of these potent antagonists revealed that the thienyl ring, the (E)-acrylic acid, and the imidazole ring in addition to the two acid groups were important for high potency.Also, overlay comparisons of the parent diacid with both angiotensin II and a representative biphenylyltetrazole nonpeptide angiotensin II receptor antagonist are presented.The parent diacid analog, SKF 108566 or (E)-3--2-propenoic acid, is currently in clinical development for the treatment of hypertension.

The thermal or photochemical decomposition of arenediazonium tetrafluoroborate salts n trifluoromethanesulfonic acid, with or without organic bases such as pyridine, provides aryl triflates in high yields.