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This article discusses the use of various compounds, such as diazo compounds, N-arylsulfonylhydrazones, and ylides, in transition-metal-free insertion reactions with organoboronic acids and their derivatives. These reactions are important for constructing C-C bonds or C-X (X = H, B) bonds. The article provides examples of specific reactions and their mechanisms, as well as the synthesis of various compounds through these reactions. It also briefly introduces the academic career and research interests of W. Jefford, who focuses on catalytic metal carbene transformations. [Extracted from the article]

Visible-Light-Responsive Nano CuO/ZnO Photocatalyst for Chan-Lam Coupling Reaction and Aerobic C(sp3)-H Bond Oxidation Semiconductor, Chan-Lam reaction, heterogeneous photocatalyst, C(sp 3)-H bond oxidation, gram-scale synthesis Keywords: semiconductor; heterogeneous photocatalyst; Chan-Lam reaction; C(sp 3)-H bond oxidation; gram-scale synthesis EN semiconductor heterogeneous photocatalyst Chan-Lam reaction C(sp 3)-H bond oxidation gram-scale synthesis 2495 2502 8 07/31/23 20230817 NES 230817 Graph The emergence of photocatalysts can be described as one of the most important developments in the chemistry world. In summary, we have reported a convenient and practical photochemical method for the Chan-Lam coupling and C(sp SP 3 sp )-H bond oxidation reactions using nano CuO/ZnO as a sustainable and cost-effective photocatalyst. [Extracted from the article]

We describe herein a three-step synthesis of aliphatic sulfinates. This cost-effective method involves the use of 2-mercaptobenzothiazole under mild conditions and exhibits good yields (up to 78% over three steps). This approach provides an access to a wide range of functionalized sulfinates. A good tolerance with respect to diverse functional groups (alkene, alkyne, ether, acetal) was also noted. [ABSTRACT FROM AUTHOR]

An efficient Pd(0)-catalyzed alkylarylation of N-alkyl-Nmethacryloylbenzamides with alkyl iodides for the synthesis of isoquinoline- 1,3-diones is described. A highlight of the method is its excellent functional-group tolerance. Mechanistic investigations suggest that a radical addition/cyclization process is probably involved in the sequences. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed Csp³-H bond mono-aroyloxylation of O-alkyl substituted oxime ethers has been developed by using 2,4,6-trimethoxybenzaldoxime as an exo-type directing group with exclusive site-selectivity. With the wide range of masked aliphatic alcohol substrates and aromatic acid coupling partners, the protocol allows rapid access to various 2-alkyl substituted glycol derivatives in synthetically useful to good yields. The employed directing group is readily removed, accordingly affording valuable functionalized aliphatic alcohols. When the solvent from hybrid DCE/HFIP to CH3CN, non-directed oxidative cross-coupling is observed between the electron-rich aromatic ring of substrates and aromatic acid partners. [ABSTRACT FROM AUTHOR]

A number of alkyl, aryl and bifunctional isothiocyanates are obtained in moderate to high yields (41-94%) in a two-step, one-pot reaction of the parent primary amines or their salts with carbon disulfide, followed by reaction of the thus formed dithiocarbamates with T3P® (propane phosphonic acid anhydride) as a new and efficient desulfurating agent. [ABSTRACT FROM AUTHOR]

N-Alkyl pipecolamides were efficiently synthesized from D-glucurono-6,3-lactone via a key 5-azido N-alkylamide intermediate that can be used as a scaffold for the synthesis of 4-amino and N-sulfonated pipecolamide derivatives. [ABSTRACT FROM AUTHOR]

A waste-free and swift protocol to synthesize symmetrical and unsymmetrical diarylmethyl thioethers from diaryl carbinols and thiols in good to quantitative yields is reported. The thiol scope included alkyl and aryl thiols bearing electron-donating and electron-withdrawing groups. Short reaction time, high atom economy, inexpensive activator, free from workup and aryl halides, and gram-scale synthesis are the significant features of the new protocol. [ABSTRACT FROM AUTHOR]

The reaction of carboxylic acid chlorides with secondary alcohols carrying either flexible alkyl or rigid aryl substituents was studied through a series of competition experiments. Aliphatic acid chlorides react preferentially with the aryl-substituted alcohols, while acid chlorides derived from aromatic carboxylic acids react with very low selectivity. Catalysis by 9-azajulolidine (TCAP) increases the selectivity strongly, while solvent and temperature effects are only moderate. The size of the alcohol substituents seems to impact selectivities only for rigid aryl substituents, and highest selectivities have been found for 1-(1-pyrenyl)ethanol. [ABSTRACT FROM AUTHOR]

A general and efficient Rh(III)-catalyzed ortho-C-H alkylation of 2-arylbenzothizazoles and 2-arylthiazoles with potassium alkyltrifluoroborates has been developed. The present method leads to the construction of a library of alkylated 2-arylbenzothiazoles and 2-arylthiazoles with yields up to 99%. [ABSTRACT FROM AUTHOR]

A new strategy towards the pharmacologically relevant class of dihydro-1,5-benzodiazepines was developed by applying a rhodiumcatalyzed asymmetric hydrogenation. The approach represents an efficient protocol providing access to the optically active products in excellent yields (up to 99%) and with high enantioselectivities (up to 92% ee). The versatility of the methodology was demonstrated by a broad substrate scope including alkyl, aryl, and heteroaryl substituents as well as halides. Furthermore, investigations regarding the reaction mechanism were performed and unraveled a preferred reaction of the tautomeric enamine in the rhodium-catalyzed asymmetric hydrogenation. [ABSTRACT FROM AUTHOR]

A simple and convenient approach for the synthesis of acylsulfenic acid alkyl esters and benzoyl alkyl disulfides from thiobenzoic acids is described. This reaction uses commercially available [bis(trifluoroacetoxy) iodo]benzene (PIFA) as an oxidant under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Our group has designed and developed 3-alkyl-2-vinylindoles as a new type of vinylindoles, which have displayed versatile reactivity in Brønsted acid catalyzed reactions. For instance, this class of vinylindoles can act as 2C building blocks in [n+2] cyclizations, as 2,3-disubstituted indoles in dearomatizations, and as NCC building blocks in [3+2] cyclodimerizations. This article summarizes the main contributions of our group in this research field. 1 Introduction 2 As 2C building blocks in [n+2] cyclizations 3 As 2,3-disubstituted indoles in dearomatization 4 As NCC building blocks in [3+2] cyclodimerizations 5 Summary and outlook [ABSTRACT FROM AUTHOR]

Alkyl 2-(alkylamino)-3-(quinolin-2-yl)indolizine-1-carboxylates were prepared by1,3-dipolar cycloaddition of azomethine ylides with phosphorylated hydroxyketenimines, generated in situ by a Nef isocyanide-Perkow cascade. [ABSTRACT FROM AUTHOR]

A simple single-step methodology was developed to synthesize 3,7-dialkyltetrahydro-1H,5H-[1,2,4]triazolo[1,2-a][1,2,4]triazole1,5-dithiones in improved yields by acid-catalyzed reaction of thiosemicarbazide and aliphatic aldehydes in anhydrous ethanol at reflux temperature. The products were obtained in good to excellent yields. A plausible mechanism involving two successive intramolecular heterocyclizations of thiosemicarbazone has also been proposed. The synthesized compounds were characterized by spectroscopic methods and confirmed by using X-ray crystallography. These C-2 symmetric hexaheteroatomic fused heterocycles are expected to have exceptional applications. [ABSTRACT FROM AUTHOR]

Site-selective and stereoselective C(sp³)-H borylation of alkyl side chains of 1,3-azoles with bis(pinacolato)diboron was effectively catalyzed by a silica-supported monophosphine-iridium catalyst. The borylation occurred under relatively mild conditions (2 mol% Ir, 50-90 °C), affording the corresponding primary and secondary alkylboro-nates. This system was applicable to a variety of 1,3-(benzo)azoles such as thiazoles, oxazoles, and imidazoles. [ABSTRACT FROM AUTHOR]

Reactions of 1,1,1-trifluoro-2-iodoethane with alkylalkenes and silyl enol ethers were performed in the presence of a catalytic amount of fac-Ir(ppy)3 and an excessive amount of Hünig's base in acetonitrile irradiated by a 24 W fluorescent lamp under nitrogen atmosphere for 48 hours. The visible-light-induced photoredox reactions introduce simultaneously a 2,2,2-trifluoroethyl group and an iodine atom to both sides of the double bond of ordinary alkenes via an atom-transfer radical addition (ATRA). The same reaction with silyl enol ethers generates β-trifluoromethyl ketones, which are typically a challenge to synthesize. The reactions proved to be tolerant of a variety of functionalities. [ABSTRACT FROM AUTHOR]

Nucleophilic addition of 1-(2-hydroxyalkyl)pyrroles to acetylene, an unactivated carbon-carbon triple bond, in the presence of a base has been studied. As a result an atom-economic synthetic method to obtain 1-[2-(vinyloxy)alkyl]pyrroles in good yields employing superbase, sodium or potassium hydroxide in dimethyl sulfoxide, systems has been developed. 1-[2-(Vinyloxy)alkyl]pyrroles are cleaved by base with the elimination of vinyl alcohol to give 1-vinylpyrroles. [ABSTRACT FROM AUTHOR]

A simple method for the preparation of alkyl 2-amino-benzo[b]thiophene-3-carboxylates is described. Alkyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylates, generated from the Gewald three-component reaction between cyclohexanones, alkyl cyanoacetates and sulfur, undergo dehydrogenation in benzonitrile under an air atmosphere to afford alkyl 2-aminoben-zo[è]thiophene-3-carboxylates in good to excellent yields. [ABSTRACT FROM AUTHOR]

A facile and convenient synthetic method for the anticancer agent elesclomol and its analogues, N′¹N′³-dialkyl-N′¹N′³-bis(arylcarbonothioyl)malonohydrazides, by the direct coupling of N-alkyl-iV-(substituted)benzothiohydrazides and substituted malonic acids using propylphosphonic anhydride (T3P®) under very mild conditions has been developed. [ABSTRACT FROM AUTHOR]

Decarboxylative thioesterification of isatoic anhydrides mediated by benzyl(triethyl)ammonium tetrathiomolybdate gave the corresponding S-alkyl or S-aryl 2-aminobenzenecarbothioate derivatives at 60 °C. At ambient temperature, organic disulfides were reductive cleaved in the presence of tetrathiomolybdate to generate thiolate anions in situ; this was followed by attack on isatoic anhydrides to give the corresponding S-alkyl or S-aryl 2-aminobenzenecarbothioate derivatives. Additionally, it was shown that multistep reactions could be performed with tetrathiomolybdate, starting with an alkyl halide as a precursor of an alkyl disulfide, which, in turn, was used for ring opening of isatoic anhydrides. [ABSTRACT FROM AUTHOR]

A facile access to the synthesis of alkyl and aryl oxime esters of ketoximes and aldoximes in high yields (90-97%) is reported. The reactions were performed using iV-[3-(methylamino)propyl]-N'-ethylcarbodiimide hydrochloride (EDCI) reagent in the presence of 4- (dimethylamino)pyridine (DMAP) as a catalyst at room temperature. The isolation and purification of products is very simple and in cases where product is solid, column chromatography is avoided. [ABSTRACT FROM AUTHOR]

The article offers information on the chemical synthesis of unsymmetrical dialkyl trisulfanes. Topics discussed are the methods of synthesis such as the coupling of chlorodisulfanes with N-arylamidothiosulfites and sequential coupling of two thiols using sulfur dichloride, the issues regarding the formation of undesirable polysulfane side products and the use of carboxy, methyl ester or tert butoxycarbonylamino groups on either or both sides of the trisulfane.

A series of highly strained [3.3.1]propellane derivatives, 1,3-dehydroadamantanes (DHAs) possessing alkyl, phenyl, and alkoxy substituents, such as 5-butyl, 5-hexyl, 5-octyl, 5-phenyl, 5- methoxy, 5-butoxy, 5,7-dimethyl, 5-ethyl-7-hexyl, 5,7-dibutyl-, 5- butyl-7-isobutyl, 5-butyl-7-hexyl, 5-butyl-7-phenyl, 5-butyl-7- methoxy, and 5-butoxy-7-butyl, were synthesized in several gram amounts. The 1,3-dibromoadamantanes carrying alkyl, phenyl, and alkoxy substituents were converted into the corresponding DHAs via the intramolecular Wurtz-type coupling reactions with lithium metal in THF in 21-81% yields. [ABSTRACT FROM AUTHOR]

Alkylzirconium reagents undergo highly enantioselective copper-catalysed 1,4-addition reaction to cyclic enones. These reactions use alkylmetal species generated in situ from alkenes and the Schwartz reagent, and do not require premade organometallic reagents. The reactions have been performed on practical synthetic scales (2.5 mmol) and a scale-up to 10 mmol is demonstrated. The reactions proceed at room temperature, in a variety of solvents, and tolerate many functional groups. [ABSTRACT FROM AUTHOR]

We have developed a convenient method for the synthesis of functionalized unsymmetrical dialkyl trisulfanes under mild conditions in very good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)- disulfanyl derivatives with alkyl disulfanyl anions generated in situ from S-acetyl disulfanyl derivatives and sodium methoxide. The developed method allows for the preparation of unsymmetrical trisulfanes bearing additional hydroxyl, carboxyl, or amino functionalities on both sides of the trisulfane functionality. [ABSTRACT FROM AUTHOR]

The combination of a tandem process with a multicomponent reaction is a new approach to high atom-economic synthesis. A tandem hydroformylation-Biginelli reaction sequence has been developed leading to a variety of functionalized 4-alkyl-substituted 3,4-dihydropyrimidin-2(1H)-ones. [ABSTRACT FROM AUTHOR]

The ruthenium photocatalyst Ru(bpy)3Cl2·6H2O has the potential to catalyze the cascade radical reaction with perfluoroalkyl radicals in aqueous media via two photoredox cycles. [ABSTRACT FROM AUTHOR]

The embodiment of lactam rings within a wealth of physiologically active natural products and pharmaceutical agents ensures that the development of synthetic methods, which facilitate the preparation of these saturated N-heterocycles, is of critical importance. Herein the development of a versatile method for the synthesis of 4 to 8-membered &agr;-vinyl and &agr;-(2-silylvinyl) lactams involving the iodine(III)-mediated oxidative cyclization of unsaturated O-alkyl hydroxamates, which encompass an allylsilane, is reported. Importantly, the outcome of this transformation can be effectively controlled through variation of the substitution pattern at the silicon center. While allyltrimethylsilanes undergo ring closure with desilylation to form &agr;-vinyl lactams, the corresponding triisopropyl and triphenylsilanes cyclize without loss of the larger silyl group to form E-vinylsilanes with excellent stereoselectivity. From a mechanistic standpoint, it is proposed that this reaction proceeds via concerted alkene addition of a singlet nitrenium ion (or its equivalent) to form a bicyclic N-acyl-N-alkoxyaziridinium ion, which undergoes eliminative ring opening. [ABSTRACT FROM AUTHOR]

The direct phosphonation of indoles was developed. In this reaction, dialkyl phosphites and indoles were used as substrates, and the C-P bond was formed through oxidative coupling mediated by silver(I) acetate. Various indoles and different dialkyl phosphites were effective substrates for the reaction, and dialkylphosphoryl-substituted indoles were obtained in up to 71% yield. [ABSTRACT FROM AUTHOR]

4-Carboxyalkyl-8-formyl coumarins have been synthesized from 2-hydroxybenzaldehydes via vinyltriphenylphosphonium salt mediated aromatic electrophilic substitution in good yields. The vinyltriphenylphosphonium salt is generated in situ by protonation of the reactive 1:1 intermediate produced by the reaction of triphenylphosphine and dialkyl acetylenedicarboxylate with 2-hydroxybenzaldehydes. [ABSTRACT FROM AUTHOR]

Using cyclopalladated ferrocenylimine complexes (1-3 mol%) as catalysts, the Suzuki-Miyaura coupling of potassium N,N-dialkylaminomethyltrifluoroborates with aryl and heteroaryl halides were carried out in a 10:1 THF-H2O mixture at 80 ˚C in the presence of Cs2CO3 (3.0 equiv) as base, giving the desired cross-coupling products in 14-87% yields. A variety of potassium alkyltrifluoroborates were also examined. [ABSTRACT FROM AUTHOR]

A simple and efficient protocol for the synthesis of Nβ-Fmoc/Z-amino alkyl thiols is described. The approach uses sodium pyrosulfite-mediated hydrolysis of isothiouronium salts resulting from the reaction between N-protected aminoalkyl iodides and thiourea. N-Protected taurines were prepared through performic acid oxidation of the thiols and the products were further utilized for the synthesis of dipeptidosulfonamides. [ABSTRACT FROM AUTHOR]

Synthetically useful Nβ-Fmoc amino alkyl isonitriles are prepared conveniently from Nβ-Fmoc amino alkyl thioformamides via a cyanogen bromide mediated dehydrosulfurization. The reaction is fast, clean, and yields are good. [ABSTRACT FROM AUTHOR]

S-(fluoroalkyl)diphenylsulfonium salts have been successfully synthesized from the reaction between fluoroalkylsul�finates and triflic anhydride in dichloromethane through a one-pot procedure. These S-(fluoroalkyl)diphenylsulfonium salts have been demonstrated to be effective reagents to fluoroalkylate C-nucleophilic substrates. Ionic substitution and radical or halogenophilic mechanism might be all involved in the reactions. [ABSTRACT FROM AUTHOR]

Alkyl and (hetero)aryl alkyne allyl alcohols can readily be transformed into chiral 4-alkyl 3-alkylidene tetrahydrofurans and tetrahydrofuranones bearing α,β-unsaturated carbonyl side chains in a one-pot fashion via an enantioselective rhodium-catalyzed �cycloisomerization-Wittig olefination sequence in good yields (54-86%). [ABSTRACT FROM AUTHOR]

A mild and efficient method has been developed for the preparation of 14-aryl- or 14-alkyl-14H-dibenzo[a,j]xanthenes from one-pot condensation of aldehydes with 2-naphthol using catalytic amount of Br�nsted acidic ionic liquid ([TEBSA][HSO4]) under thermal solvent-free conditions. Excellent yields, short reaction times, easy workup and reusability of the catalyst as well as solvent-free conditions are advantages of this procedure. [ABSTRACT FROM AUTHOR]

The efficient and very simple conjugate addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds under solvent-free conditions in the presence of catalytic amount of silicon tetrachloride is reported. The reaction of aryl and alkyl amines with different Michael acceptors gave the corresponding Michael adducts with simple catalyst and good to excellent yields. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of perfluoroalkyl allenyl ketones via the 1,2-addition-elimination reaction of per�fluoroalkyl Grignard reagents with allenoates has been established. No further reaction was observed between these perfluoroalkyl ketones and RfMgX. Under the catalysis of PdCl2 or AuCl3, perfluoroalkyl 1,2-allenyl ketones can be transformed to 2-perfluoroalkyl-substituted furans; they may also undergo 1,2-addition with organolithiums to afford tertiary 1,2-allenols containing a perfluoroalkyl group. [ABSTRACT FROM AUTHOR]

A new, short, and simple synthetic approach to sulfonyl ureas is reported. The method involves the transformation of readily synthesized N-alkyl-1,2,4-dithiazolidine-3,5-diones by reaction with primary sulfonamides. Sulfonyl ureas were obtained in moderate to high yields. [ABSTRACT FROM AUTHOR]

Providencin is a novel, highly oxygenated marine furanocembranolide featuring a cyclobutane ring and a highly strained 7,8-trans-epoxide. Various approaches to the total synthesis of this compound are reported. The cyclobutane moiety is generated via [2+2] cycloaddition and the furan ring is constructed via a Wipf �palladium-catalyzed alkynone cyclization. The macrocyclic ring is closed via a Horner-Wadsworth-Emmons olefination or ring-�closing metathesis. The latter reaction, however, produces the undesired 7,8-Z-olefin exclusively, and the conversion into the E-isomer has been, thus far, unsuccessful. 1 Introduction 2 Retrosynthetic Analysis 3 First Generation Approach 3.1 Synthesis of the Cyclobutane Moiety 3.2 Synthesis of the Western Fragment 3.3 Combination of Both Fragments and Ring Closure via [nl]Horner-Wadsworth-Emmons Olefination 4 Second Generation Approach via Ring-Closing Metathesis 5 Cyclobutane Model Studies 6 Conclusion [ABSTRACT FROM AUTHOR]

Highly enantioselective aminations of acyclic α-alkyl β-keto thioesters and trifluoroethyl α-methyl α-cyanoacetate (12) with as low as 0.05 mol% of a bifunctional cinchona alkaloid catalyst were established. This ability to afford high enantioselectivity for the amination of α-alkyl β-carbonyl compounds renders the 6′-OH cinchona alkaloid-catalyzed amination applicable for the enantio�selective synthesis of acyclic chiral compounds bearing N-substituted quaternary stereocenters. The synthetic application of this reaction is illustrated in a concise asymmetric synthesis of α-methylserine, a key intermediate previously utilized in the total synthesis of a small molecule immunomodulator, conagenin. [ABSTRACT FROM AUTHOR]

The first synthesis of an alkyltetrahydropyran using a �diarylprolinol organocatalyst is described. [ABSTRACT FROM AUTHOR]

Regioselective Grignard reagent additions to 3-methoxymaleimides and subsequent diastereoselective reductive dehydroxylation of the resulting N,O-acetals were studied. On the basis of these studies, a flexible and highly regio- and diastereoselective approach to methyl 5-alkyltetramate derivatives was disclosed. The method is the first direct and flexible asymmetric cationic synthon-based approach, and allows for the synthesis of various methyl (5S)-5-alkyltetramate derivatives that are otherwise inaccessible by the commonly used methods based on α-amino acids. [ABSTRACT FROM AUTHOR]

Hydroxyalkyl thiazoline ligands can easily be obtained in an isonitrile-based multicomponent reaction. These ligands are significantly more stable than the comparable oxazoline ligands, and give excellent enantiomeric excess in carbonyl additions of alkyl- and arylzinc compounds. [ABSTRACT FROM AUTHOR]

Upon treatment with DAST (diethylaminosulfur trifluoride) enantiopure 2-hydroxyalkylazetidines rearrange into 3-fluoropyrrolidines. The reaction is stereospecific and involves a bicyclic 1-azoniabicyclo[2.1.0]pentane intermediate which is regioselectively opened by a fluoride anion. [ABSTRACT FROM AUTHOR]

Electrophilic additions to 1-cyclopropylallenes were investigated, providing an efficient and stereoselective method for the synthesis of 6-substituted-1,3-hexadienes. [ABSTRACT FROM AUTHOR]

The copper-catalyzed coupling of diaryl disulfides with alkyl amines can afford various sulfenamides in good yields. Furthermore, the present reaction is efficient and can be used for both of the aryl sulfide groups on disulfide. [ABSTRACT FROM AUTHOR]