Arylation of Styrenes with Aryliron Complexes [CpFe(CO)₂Ar]

Abstract

Treatment of aryliron complexes [CpFe(CO)2Ar] with styrenes in boiling xylene affords the corresponding stilbenes. The aryliron complexes, which become active upon heating, serve as arylating agents in the reaction.

Arylation of styrene derivatives using aryliron complexes [CpFe(CO)2Ar] revealed by density functional theory calculations: Fe(II)-assisted group exchange through Fe–C bond cleavage and Fe–X bond formation

“…From Fig. 4, we can make certain that B1 is obviously the reasonable byproducts with lower relative energy, which agrees well with the experimental observations [3].…”

“…We propose that each of these reactions should mainly include three important steps (Scheme 1): (1) a ligand exchange process (dissociation of one carbonyl ligand and subsequent addition of styrene ( Scheme 1A) or a-CF 3 substituted styrene (Scheme 1B) to the metal center); (2) migration of Ar from Fe to b-C of styrene; (3) b-H elimination [16,17] or b-F elimination and subsequent dissociation of the stilbene derivative from the CpFeHCO moiety.…”

“…We firstly examined the detailed mechanism for arylation of styrene with aryliron complex [CpFe(CO) 2 Ar] (R1), using [CpFe-(CO) 2 Ar] (Ar ¼ tolyl) and styrene (R2) as model reactants, which originates from the experiments implemented by Yorimitsu [3]. For all the potential energy profiles calculated in this work, the corresponding figures are presented with the calculated relative free energies and relative electronic energies.…”

“…Recently, Yorimitsu, Oshima and Yasuda reported an experimental observation regarding reactions of [CpFe(CO) 2 Ar] with styrenes to give the corresponding stilbenes [3]. In their experiments, [CpFe(CO) 2 (4-tolyl)] could react with styrene in refluxing xylene to afford 4-methylstilbene in 79% yield (Eq.…”

Photochemical Heck benzylation of styrenes catalyzed by Na[FeCp(CO)2]

“…Recently, Yasuda et al disclosed the stoichiometric arylation of styrenes by Fp-Ar reagents at high temperatures ( Figure 1a) [33]. In principle, this transformation could serve as the basis for a closed catalytic cycle for Heck coupling (Figure 1b) if only the aryliron(II) bond could be installed by activation of an Ar-X reagent by Fp -.…”