Iron-Catalyzed Oxidative Monoarylation of Primary Amines with Organozinc Reagents

The reaction of a primary zinc amide with a diorganozinc reagent gives a secondary amine in the presence of Fe(acac)3 as a catalyst and 1,2-dichloroisobutane (DCIB) as an oxidant. Halogen groups such as F, Cl, Br, and I are tolerated well. The dichloride oxidant and heat are essential to achieve the C–N bond formation presumably from a catalytic iron intermediate species bearing aryl and amido groups

Iron-Catalyzed Allylic Arylation of Olefins via C(sp³)–H Activation under Mild Conditions

An aryl Grignard reagent in the presence of mesityl iodide converts an allylic C–H bond of a cycloalkene or an allylbenzene derivative into a C–C bond in the presence of a catalytic amount of Fe(acac)3 and a diphosphine ligand at 0 °C. The stereo- and regioselectivity of the reaction, together with deuterium labeling experiments, suggest that C–H bond activation is the slow step in the catalytic cycle preceding the formation of an allyliron intermediate

Synthesis of Benzo[<i>b</i>]siloles via KH-Promoted Cyclization of (2-Alkynylphenyl)silanes

(2-Alkynylphenyl)silanes undergo intramolecular cyclization in the presence of an excess or a subequimolar amount of potassium hydride to give a variety of new 2-substituted benzosiloles in good to excellent yields. Some of these compounds showed a high fluorescence quantum yield both in solution and in the solid state, and they also showed reversible reduction in THF

Nickel-Catalyzed Synthesis of Diarylamines via Oxidatively Induced C–N Bond Formation at Room Temperature

A nickel-catalyzed oxidative coupling of zinc amides with organomagnesium compounds selectively produces diarylamines under mild reaction conditions, with tolerance for chloride, bromide, hydroxyl, ester, and ketone groups. A diamine is bis-monoarylated. A bromoaniline undergoes <i>N</i>-arylation followed by Kumada–Tamao–Corriu coupling in one pot. The reaction may proceed via oxidatively induced reductive elimination of a nickel species

Iron-Catalyzed Stereospecific Activation of Olefinic C–H Bonds with Grignard Reagent for Synthesis of Substituted Olefins

The reaction of an aryl Grignard reagent with a cyclic or acyclic olefin possessing a directing group such as pyridine or imine results in the stereospecific substitution of the olefinic C–H bond syn to the directing group. The reaction takes place smoothly and without isomerization of the product olefin in the presence of a mild oxidant (1,2-dichloro-2-methylpropane) and an aromatic cosolvent. Several lines of evidence suggest that the reaction proceeds via iron-catalyzed olefinic C–H bond activation rather than an oxidative Mizoroki–Heck-type reaction

Phenanthrene Synthesis by Iron-Catalyzed [4 + 2] Benzannulation between Alkyne and Biaryl or 2-Alkenylphenyl Grignard Reagent

The [4 + 2] benzannulation reaction of internal or terminal alkynes with 2-biaryl, 2-heteroarylphenyl, or 2-alkenylphenyl Grignard reagents in the presence of Fe(acac)3, 4,4′-di-tert-butyl-2,2′-bipyridyl, and 1,2-dichloro-2-methylpropane takes place at room temperature in 1 h to give 9-substituted or 9,10-disubstituted phenanthrenes and congeners in moderate to excellent yields. The reaction tolerates sensitive functional groups such as bromide and olefin. When applied to a 1,3-diyne, the annulation reaction takes place on both acetylenic moieties to give a bisphenanthrene derivative

Iron-Catalyzed Regio- and Stereoselective Chlorosulfonylation of Terminal Alkynes with Aromatic Sulfonyl Chlorides

Terminal alkynes react with aromatic sulfonyl chlorides in the presence of an iron(II) catalyst and a phosphine ligand to give (<i>E</i>)-β-chlorovinylsulfones with 100% regio- and stereoselectivity. Various functional groups, such as chloride, bromide, iodide, nitro, ketone, and aldehyde, are tolerated under the reaction conditions. Addition of tosyl chloride to a 1,6-enyne followed by radical 5-<i>exo</i>-<i>trig</i> cyclization gave an exocyclic alkenylsulfone

Cobalt-Catalyzed <i>ortho</i>-Alkylation of Secondary Benzamide with Alkyl Chloride through Directed C−H Bond Activation

Coupling of an alkyl chloride with a secondary benzamide derivative at the ortho-position can be achieved in good to excellent yield in the presence of a cobalt catalyst and cyclohexylmagnesium chloride in diethyl ether at room temperature. Cyclohexylmagnesium chloride formally acts to remove hydrogen atoms from the amide nitrogen and from the ortho-position and to generate the active cobalt species

Synthesis of Functionalized 1<i>H</i>-Indenes via Copper-Catalyzed Arylative Cyclization of Arylalkynes with Aromatic Sulfonyl Chlorides

A variety of polysubstituted 1H-indenes can be prepared through the copper-catalyzed arylative cyclization of simple arylalkynes with commercially available aromatic sulfonyl chlorides that function as an aryl group donor. The reaction tolerates a broad range of functional groups, including bromide and iodide, nitrile, ketone, and nitro groups. The reaction allowed the synthesis of polycyclic aromatic hydrocarbons, such as a bis(indene), indacene, and fused polyarene derivatives, some of them showing strong fluorescence in solution and the solid state

Synthesis of Benzo[<i>b</i>]siloles via KH-Promoted Cyclization of (2-Alkynylphenyl)silanes

(2-Alkynylphenyl)silanes undergo intramolecular cyclization in the presence of an excess or a subequimolar amount of potassium hydride to give a variety of new 2-substituted benzosiloles in good to excellent yields. Some of these compounds showed a high fluorescence quantum yield both in solution and in the solid state, and they also showed reversible reduction in THF