Electrophilic and Radical Substitution of 1,2,5-Cobaltadithiolenes

Rare direct imidation of aromatic metallacycle by reaction of CpCo(dithiolene) complex with N-halosuccinimide

“…We have reported carbon-centered radical substitution reactions by 1-cyano-1-ethylmethyl radical to the dithiolene ring and to the Cp ligand of 1 [11]. The carbon-centered radical substitution occurs to the square-planar [Ni(S 2 C 2 (Ph)(H)) 2 ] complex as well [12b].…”

“…Generally, one chemical reactivity due to aromaticity is a substitution reaction on the ring. In fact, electrophilic substitution and radical substitution reactions occur on the cobaltadithiolene ring, while the ring has hydrogen atom on the dithiolene carbon [11,12]. Namely, this metal chelate ring also behaves like an organic aromatic ring.…”

Pd-catalyzed boronations and cross-coupling reactions of aromatic cobaltadithiolene complexes with aryl halides

“…The ring undergoes electrophilic substitution reactions (Friedel-Crafts type) [10], carbon-centered [10,11], sulfur-centered and nitrogen-centered radical substitution reactions [12]. Recently, we focused on some coupling reactions of the cobaltadithiolene ring, because it is one representative reactivity of an aryl group.…”

Sulfur-centered and nitrogen-centered radical substitution reactions of aromatic CpCo(dithiolene) complex with 2,2′-Dibenzothiazolyl disulfide

“…Addition reactions involve alkylidene-, imido-, alkyne-, and norbornene-addition into the MeS bond due to unsaturation of the metallacycle [8]. On the basis of aromaticity of the metallacycle, the Friedel-Crafts acylation occurs on the dithiolene carbon of [CpCo(S 2 C 2 (R)(H))] complex in the presence of Lewis acid [9]. Quite recently, we reported the Suzuki-Miyaura cross-coupling reaction between the boronated [CpCo(S 2 C 2 (Ph)(Bpin))] (Bpin ¼ 4,4,5,3, complex and aryl halides in the presence of Pd catalyst [10].…”

“…For example, [CpCo(S 2 C 2 (Ph)(H))] complex reacts with 1-cyano-1-ethylmethyl radical, which can be generated from thermolysis of 2,2 0 -azobis(isobutyronitrile) (AIBN) [11], to undergo radical substitutions on the dithiolene ring and on the Cp ring as well (Scheme 1) [9]. The former reaction has been the first case of radical substitution reaction to a pseudo aromatic metallacycle.…”