Convenient lanthanum-mediated synthesis of bulky tert-alkyl amines from nitriles

Tert-alkyl amines can be conveniently prepared in one step from nitriles by a double addition of ethyl or propyl Grignard reagent mediated by a commercially available lanthanum chloride-lithium chloride complex solution. The reaction operates on a variety of benzonitriles, with several heterocyclic nitriles and an alkyl nitrile also being suitable substrates.

1- and 2-Tetrazolylacetonitrile as Versatile Ligands for Laser Ignitable Energetic Coordination Compounds

1- and 2-Tetrazolylacetonitrile (1- and 2-TAN) have been synthesized by the reaction of chloroacetonitrile with 1H-tetrazole under basic conditions. They further were reacted with sodium azide in the presence of zinc(II) chloride to form 5-((1H-tetrazol-1-yl)methyl)-1H-tetrazole (1-HTMT) and 5-((2H-tetrazol-2-yl)methyl)-1H-tetrazole (2-HTMT). The nitrogen-rich compounds have been applied as ligands for Energetic Coordination Compounds (ECCs) and show interesting coordinative behavior due to different bridging modes. The structural variability of the compounds has been proved by low-temperature X-ray analysis. The ECCs were analyzed for their sensitivities to provide information about the safety of handling and their capability to serve as primary explosives in detonator setups to replace the commonly used lead styphnate and azide. All colored ECCs were evaluated for their ignitability by laser initiation in translucent polycarbonate primer caps. In addition, the spin-crossover characteristics of [Fe(1-TAN)6](ClO4)2 were highlighted by the measurement of the temperature-dependent susceptibility curve.

Nickel-catalyzed asymmetric reductive arylcyanation of alkenes with acetonitrile as the cyano source

Chiral 3-cyanomethyl oxindoles were synthesized in high enantioselectivities and yields. The employment of acetonitrile as a cyano source via Zn(OTf)2-assisted β-carbon elimination is distinct from the common cyanation reaction modes.

Paired Electrolysis for Decarboxylative Cyanation: 4-CN-Pyridine, a Versatile Nitrile Source

A decarboxylative cyanation of amino acids under paired electrochemical reaction conditions has been developed. 4-CN-pyridine was found to be a new and effective cyanation reagent under catalyst-free conditions. Mechanistic studies support a nucleophilic reaction pathway, and the cyanation protocol can be applied to diverse substrates including N,N-dialkyl aniline and indole derivatives.

C-H bond activation and sequential addition to two different coupling partners: a versatile approach to molecular complexity

Sequential multicomponent C-H bond addition is a powerful approach for the rapid, modular generation of molecular complexity in a single reaction. In this approach, C-H bonds are typically added across π-bonds or π-bond isosteres, followed by subsequent coupling to another type of functionality, thereby forming two σ-bonds in a single reaction sequence. Many sequential C-H bond addition reactions have been developed to date, including additions across both conjugated and isolated π-systems followed by coupling with reactants such as carbonyl compounds, cyanating reagents, aminating reagents, halogenating reagents, oxygenating reagents, and alkylating reagents. These atom-economical reactions transform ubiquitous C-H bonds under mild conditions to more complex structures with a high level of regiochemical and stereochemical control. Surprising connectivities and diverse mechanisms have been elucidated in the development of these reactions. Given the large number of possible combinations of coupling partners, there are enormous opportunities for the discovery of new sequential C-H bond addition reactions.

Electrosynthesis of (hetero)aryl nitriles from α-imino-oxy acids via oxidative decarboxylation/N-O cleavage

A new method for the synthesis of (hetero)aryl nitriles via iminyl radicals has been developed through the electrochemical oxidative decarboxylation of α-imino-oxy acids. This protocol provides an efficient approach to nitriles with a broad range of functional-group tolerance under ambient conditions and can be applied for one-pot gram-scale synthesis.

Palladium-catalyzed direct construction of oxazoline-containing polycyclic scaffolds via tandem addition/cyclization of nitriles and arylboronic acids

An efficient construction of oxazoline-containing polycyclic scaffolds through a Pd-catalyzed addition/cyclization of (hetero)arene tethered O-acyl cyanohydrin units and arylboronic acids is described.

Iterative addition of carbon nucleophiles to N,N-dialkyl carboxamides for synthesis of α-tertiary amines

A protocol for the synthesis of α-tertiary amines was developed by iterative addition of carbon nucleophiles to N,N-dialkyl carboxamides. Nucleophilic 1,2-addition of organolithium reagents to carboxamides forms anionic tetrahedral carbinolamine (hemiaminal) intermediates, which are subsequently treated with bromotrimethylsilane (Me₃SiBr) followed by organomagnesium (Grignard) reagents, organolithium reagents or tetrabutylammonium cyanide, affording α-tertiary amines. Employment of (trimethylsilyl)methylmagnesium bromide as the 2^nd nucleophile allowed for aza-Peterson olefination of the resulting α-tertiary (trimethylsilyl)methylamines with acidic work-up, resulting in the formation of 1,1-diarylethylenes.

Highly Regioselective Aromatic C-H Allylation of N-(Arylmethyl)sulfonimides with Allyl Grignard Reagents Involving Benzylic C-N Cleavage

A new pair of reaction partners has been established for the aromatic C-H functionalization of benzyl electrophiles with nucleophiles via palladium-catalyzed benzylic C-N cleavage. A range of N-(1-naphthylmethyl)sulfonimides, N-(2-thienylmethyl)sulfonimides, and N-(2-furanylmethyl)sulfonimides smoothly underwent palladium-catalyzed aromatic C-H allylation with allyl Grignard reagents at room temperature, delivering structurally diverse substituted 1-allylnaphthalenes and 2-allylheteroarenes in moderate to excellent yields with extremely high regioselectivities. Replacing the N-(arylmethyl)sulfonimide with an (arylmethyl)ammonium salt, an arylmethyl chloride, or an arylmethyl phosphate as the benzyl electrophile leads to a dramatic erosion of the regioselectivity.

Pd-catalyzed sp-sp3 cross-coupling of benzyl bromides using lithium acetylides

Organolithium-based cross-coupling reactions have emerged as an indispensable method to construct C–C bonds. These transformations have proven particularly useful for the direct and fast coupling of various organolithium reagents (sp, sp², and sp³) with aromatic (pseudo) halides (sp²). Here we present an efficient method for the cross-coupling of benzyl bromides (sp³) with lithium acetylides (sp). The reaction proceeds within 10 min at room temperature and can be performed in the presence of organolithium-sensitive functional groups such as esters, nitriles, amides and boronic esters. The potential application of the methodology is demonstrated in the preparation of key intermediates used in pharmaceuticals, chemical biology and natural products.

A fast and highly selective method for cross-coupling of benzyl bromides with lithium acetylides, proceeding at room temperature in 10 min while tolerating various organolithium-sensitive functional groups, is presented.

Cyanoalkylation/alkynylation of allylic alcohol through intramolecular radical 1,2-alkynyl migration

A di-tert-butyl peroxide (DTBP)-promoted difunctionalization of α-aryl α-alkynyl allylic alcohols with alkyl nitriles was developed, affording a series of α-alkynyl γ-cyano functionalized ketones in moderate yields. This procedure involved C(sp³)-H bond cleavage of alkyl nitriles and radical 3-exo-dig cyclization. After this, radical 1,2-alkynyl migration is preferred rather than 1,2-aryl migration.

Synthesis of Nitrile Bearing Acyclic Quaternary Centers through Co(III)-Catalyzed Sequential C-H Bond Addition to Dienes and N-Cyanosuccinimide

Herein we disclose a three-component strategy to access quaternary centers bearing nitriles by cobalt-catalyzed C-H bond activation and sequential addition to internally substituted 1,3-dienes and an electrophilic cyanating reagent with high regio and stereocontrol. 2-Aryl and alkyl monosubstituted dienes provide α-aryl and α-alkyl α-methyl-substituted nitriles, respectively. An even wider variety of functionality can be installed at the quaternary carbon by using 1,2-disubstituted dienes. The synthetic utility of the nitrile products was successfully demonstrated by various transformations, including conversions to γ-lactones and tetrazoles. The observed connectivity in the products along with studies with deuterium labeled reactants provide insight into the mechanism. Formation of a 7-membered cobaltacycle by C-H activation and migratory insertion of the diene is followed by β-hydride elimination and hydride reinsertion to give a 6-membered cobaltacycle that then reacts with the cyanating agent.

IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: a photochemical pathway

An unprecedented Ir^III[df(CF₃)ppy]₂(dtbbpy)PF₆-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein.

Successive addition of two different Grignard reagents to nitriles: access to α,α-disubstituted propargylamine derivatives

The successive addition of two different Grignard reagents to acyl cyanohydrins was performed with success by taking advantage of the low reactivity of alkynyl Grignard reagents. The experimental conditions were adjusted so that they were not reactive during the first addition step, but reactive only in the second one. The synthetic utility of the prepared compounds was validated by the preparation of chiral quaternary α-amino acids.

Unprecedented Nucleophilic Additions of Highly Polar Organometallic Compounds to Imines and Nitriles Using Water as a Non-Innocent Reaction Medium

In contrast to classic methods carried out under inert atmospheres with dry volatile organic solvents and often low temperatures, the addition of highly polar organometallic compounds to non-activated imines and nitriles proceeds quickly, efficiently, and chemoselectively with a broad range of substrates at room temperature and under air with water as the only reaction medium. Secondary amines and tertiary carbinamines are furnished in yields of up to and over 99 %. The significant solvent D/H isotope effect observed for the on-water nucleophilic additions of organolithium compounds to imines suggests that the on-water catalysis arises from proton transfer across the organic-water interface. The strong intermolecular hydrogen bonds between water molecules may play a key role in disfavoring protonolysis, which occurs extensively in other protic media such as methanol. This work lays the foundation for reshaping many fundamental s-block metal-mediated organic transformations in water.