Tosyl Cyanide Research Articles

Stereoselective Construction of Less-Accessible Acyclic α,α-Disubstituted β-Ketiminonitriles via Electrophilic Cyanation of β,β-Disubstituted Enesulfinamides.

The metalloenamines, formed by NH-deprotonation of β,β-disubstituted enesulfinamides, can undergo reactions with commercially available electrophilic cyanating reagents such as tosyl cyanide (TsCN) or 3-oxo-1,2-benziodoxole-1(3H)-carbonitrile (CBX). Through the utilization of appropriate stereoisomers of enesulfinamides, this method enables the selective synthesis of any of the four stereoisomers of α,α-disubstituted β-sulfinylimino nitriles, which feature acyclic quaternary stereocenters and are typically more challenging to synthesize. These compounds can then undergo stereoselective nucleophilic addition, leading to the creation of valuable enantioenriched multisubstituted β-amino carbonyl surrogates with a high degree of structural diversity.

Photo-induced radical transformations of tosyl cyanide.

Tosyl cyanide is a commonly used reagent for cyanation and sulfonylation in organic synthesis and pharmaceutical chemistry. The photocatalytic transformations of tosyl cyanide are generally conducted under mild conditions. This minireview summarizes the recent progress of radical-involved transformations of tosyl cyanide via photo-induced cyanation or sulfonylcyanation.

Water-mediated radical C-H tosylation of alkenes with tosyl cyanide.

The water-mediated tosylation of alkenes with tosyl cyanide was discovered. Experimental investigations revealed that the reaction was initiated by the in situ formation of sulfinyl sulfone in the presence of water. The sulfinyl sulfone species decomposed to a sulfonyl radical and a sulfinyl radical through homolytic fission. The vinyl sulfone was afforded via sequential addition of the alkene to the sulfonyl radical and the sulfinyl radical, followed by β-elimination of a sulfinyl moiety.

Preparation of Highly-Substituted Pyridines via Diels-Alder Reactions of Vinylallenes and Tosyl cyanide

Preparation of Highly-Substituted Pyridines via Diels-Alder Reactions of Vinylallenes and Tosyl cyanide

Preparation of Polyfunctionalized Aromatic Nitriles from Aryl Oxazolines.

A selective ortho,ortho’‐functionalization of readily available aryl oxazolines by two successive magnesiations with sBu2Mg in toluene followed by trapping reactions with electrophiles, such as (hetero)aryl iodides or bromides, iodine, tosyl cyanide, ethyl cyanoformate or allylic bromides (39 examples, 62–99 % yield) is reported. Treatment of these aryl oxazolines with excess oxalyl chloride and catalytic amounts of DMF (50 °C, 4 h) provided the corresponding nitriles (36 examples, 73–99 % yield). Conversions of these nitriles to valuable heterocycles are reported, and a tentative mechanism is proposed.

Highly Regioselective Addition of Allylic Zinc Halides and Various Zinc Enolates to [1.1.1]Propellane.

We report a range of highly regioselective openings of [1.1.1]propellane with various allylic zinc halides, as well as zinc enolates of ketones, esters and nitriles. The resulting zincated bicyclopentanes (BCPs) were trapped with a range of electrophiles including acyl chlorides, sulfonothioates, hydroxylamino benzoates, tosyl cyanide as well as aryl and allyl halides, generating highly functionalized BCP‐derivatives. The unusually high regioselectivity of these reactions has been rationalized using DFT calculations. A bioisostere of the synthetic opioid pethidine was prepared in 95 % yield in one step using this method.

Synthesis of 1,2-dicyanoferrocene by cyanation reactions

We report two synthetic pathways for the preparation of 1,2-dicyanoferrocene, in a search for new dinitrile-based precursors that could be useful in the synthesis of metallocene-containing azaporphyrins, as well as in catalysis. Both procedures include cyanation reactions as the key steps. Magnesiation of cyanoferrocene, followed by reaction with electrophilic tosyl cyanide, affords the target compound in only two synthetic steps from ferrocene. In addition, 1,2-dicyanoferrocene can be prepared by a three step procedure, which implies a twofold cyanation of 1,2-dibromoferrocene, using Zn(CN)[Formula: see text], in a biphasic medium and in the presence of bulky [Formula: see text]-BuXPhos-Pd-G3.

Organophotoredox assisted cyanation of bromoarenes via silyl-radical-mediated bromine abstraction.

The insertion of a nitrile (-CN) group into arenes through the direct functionalization of the C(sp2)-Br bond is a challenging reaction. Herein, we report an organophotoredox method for the cyanation of aryl bromides using the organic photoredox catalyst 4CzIPN and tosyl cyanide (TsCN) as the nitrile source. A photogenerated silyl radical, via a single electron transfer (SET) mechanism, was employed to abstract bromine from aryl bromide to provide an aryl radical, which was concomitantly intercepted by TsCN to afford the aromatic nitrile. A range of substrates containing electron-donating and -withdrawing groups was demonstrated to undergo cyanation at room temperature in good yields.

Synthesis and ε-Caprolactone Polymerization Activity of Electron-Deficient Gallium and Aluminum Species Containing a Charged Redox-Active dpp-Bian Ligand.

The synthesis of electron-deficient gallium- and aluminum-centered species containing a redox-active dpp-Bian ligand (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) is described. The reaction of digallane [(dpp-Bian)Ga-Ga(dpp-Bian)] with [Ph3C][PF6] or AgPF6 resulted in polyoxidized species [(dpp-Bian)GaF2]2 (1), [(dpp-Bian)H2][PF6] (2), and [(dpp-Bian)GaF(O2PF2)]2 (3). The reaction of digallane with B(C6F5)3 led to electron-deficient gallylene [(dpp-Bian)GaB(C6F5)3] 4 of a dpp-Bian radical anion. The soft oxidation of digallane with tosyl cyanide gave the trinuclear cationic species [(dpp-Bian)Ga(Tos)3Ga(Tos)3Ga(dpp-Bian)][Ga(CN)4] (5) containing dpp-Bian radical anions. The reaction of [(dpp-Bian)AlEt2] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the cationic complex [(dpp-Bian)AlEt2][B(C6F5)4] (6) of neutral dpp-Bian, while the treatment of [(dpp-Bian)AlEt(Et2O)] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the compound [(dpp-Bian)AlEt(Et2O)][B(C6F5)4] (7) of a dpp-Bian radical anion. The reaction of diethylaluminum derivative [(dpp-Bian)AlEt2] with 1 equiv of B(C6F5)3 gave the cationic complex [{(dpp-Bian)AlEt}2F][EtB(C6F5)3] (8) containing radical-anion dpp-Bian ligands. The paramagnetic compounds 1, 2, 4, 5, 7, and 8 were characterized by electron paramagnetic resonance spectroscopy, and the diamagnetic complex 6 was characterized by NMR spectroscopy. The molecular structures of 1-6 and 8 were established by single-crystal X-ray diffraction analysis. Compounds 4 and 6-8 were found to be active initiators for immortal ring-opening polymerization of ε-caprolactone.

Catalytic, metal-free sulfonylcyanation of alkenes via visible light organophotoredox catalysis.

The group transfer radical addition of olefins with tosyl cyanide has been accomplished via visible light-induced organophotoredox catalysis. A diverse array of olefins is amenable to this protocol, furnishing β-sulfonyl nitriles with excellent efficiency under metal-free and redox-neutral conditions. A closed catalytic cycle is operative in this transformation, providing complementary reactivity to the classic radical chain process.

ChemInform Abstract: Deboronative Cyanation of Potassium Alkyltrifluoroborates via Photoredox Catalysis.

AbstractA direct cyanation of alkyl trifluoroborates by tosyl cyanide provides the corresponding nitriles under mild reaction conditions via a radical pathway.

Visible-Light-Mediated Alkenylation, Allylation, and Cyanation of Potassium Alkyltrifluoroborates with Organic Photoredox Catalysts

Iridium- and ruthenium-free approaches to protected allylic amines and alkyl nitriles under photoredox conditions are reported. An inexpensive organic dye, eosin Y, catalyzes coupling of Boc-protected potassium α-aminomethyltrifluoroborates with a variety of substituted alkenyl sulfones through an α-aminomethyl radical addition–elimination pathway. Allylic and homoallylic amines were formed in moderate yields with high E/Z selectivity. The mechanistic approach was extended using tosyl cyanide as a radical trap, enabling the conversion of alkyltrifluoroborates to nitriles via a Fukuzumi acridinium-catalyzed process.

Photoinduced Direct Cyanation of C(sp3)-H Bonds

A general and practical synthetic protocol for the direct transformation of unreactive C(sp3)–H bonds to C(sp3)–CN bonds has been developed. The homolytic cleavage of the C–H bond is initiated by photo-excited benzophenone, and the resulting carbon radical subsequently reacts with tosyl cyanide to afford the corresponding nitrile in a highly efficient manner. The present methodology is widely applicable to various starting materials including ethers, alcohols, amine derivatives, alkanes, and alkylbenzenes. This newly developed C–H cyanation protocol provides a powerful tool for selective one-carbon elongation for the construction of architecturally complex molecules.

Tosyl cyanide as a C-sulfinylating agent: 3-sulfinylation of 4-hydroxycoumarins and related heterocycles

Treatment of 4-hydroxycoumarins and related heterocycles with TsCN under mild basic reaction conditions produces the corresponding 3-sulfinylated products in high yields. Sulfinyl transfer is proposed to occur from sulfinyl cyanate 1, generated in situ by base-catalysed rearrangement of TsCN.

Photochemically Induced Radical Transformation of C(sp3)–H Bonds to C(sp3)–CN Bonds

A general protocol for direct transformation of unreactive C(sp(3))-H bonds to C(sp(3))-CN bonds has been developed. The C-H activation was effected by photoexcited benzophenone, and the generated carbon radical was subsequently trapped with tosyl cyanide to afford the corresponding nitrile in a highly efficient manner. The present methodology is widely applicable to versatile starting materials and, thus, serves as a powerful tool for selective one-carbon elongation for construction of architecturally complex molecules.

Mild Cobalt‐Catalyzed Hydrocyanation of Olefins with Tosyl Cyanide.

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Mild Cobalt‐Catalyzed Hydrocyanation of Olefins with Tosyl Cyanide

Sanftmütig und wohlerzogen: Eine konzeptionell neue Hydrocyanierung für nichtaktivierte Olefine liefert unter milden Bedingungen sekundäre und tertiäre Nitrile in guten Ausbeuten. Herausragende Merkmale dieses Prozesses sind Toleranz für eine Vielfalt an funktionellen Gruppen, leicht zugängliche Ausgangsmaterialien und einfache Durchführbarkeit.

Mild Cobalt‐Catalyzed Hydrocyanation of Olefins with Tosyl Cyanide

Mild Cobalt‐Catalyzed Hydrocyanation of Olefins with Tosyl Cyanide

Radical Functionalization of B-Alkylcatecholboranes

Herein, a very elegant and useful method for the functionalization of alkenes by means of the radical reaction of the derived B-alkyl­catecholboranes with vinyl sulfones is described. Phenyl sulfones of various kinds, bearing a conjugated multiple bond, including tosyl cyanide, can be involved in this reaction. Although the method was demonstrated on unfunctionalized polycyclic alkenes, the mild conditions of the reaction offer good functional-group compatibility. The synthetic usefulness of this approach was demonstrated on a number of very interesting transformations of some alkenes.

2-azabicyclo[2.2.2]octa-3,5-dione via a nitrile Diels-Alder reaction.

The hetero-Diels-Alder reaction of an electron-deficient nitrile, p-toluenesulfonyl cyanide, with the silyl enol ether of cyclohexenone produced a hydrolytically sensitive [4 + 2] adduct in good yield. Use of Mander's reagent, ethyl cyanoformate, with the same diene, produced an unstable adduct. Hydrolysis of the tosyl cyanide adduct resulted in the isoquinuclidinone 2-aza[2.2.2]octa-3,5-dione as a crystalline compound in excellent yield from the nitrile.