Quantum Chemical Study of the Addition of Secondary Phosphine Chalcogenides to Vinyl Selenides
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tum Chemical Study of the Addition of Secondary Phosphine Chalcogenides to Vinyl Selenides Ya. A. Vereshchaginaa,*, R. R. Ismagilovaa, D. V. Chachkovb, and N. A. Chernyshevac a b
Kazan (Volga Region) Federal University, Kazan, 420008 Russia
Kazan Branch, Joint Supercomputer Center, Russian Academy of Sciences (Branch of “Scientific Research Institute for System Analysis” Federal Research Center, Russian Academy of Sciences), Kazan, 420111 Russia c
Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, 664033 Russia *e-mail: [email protected] Received June 2, 2020; revised June 11, 2020; accepted June 22, 2020
Abstract—DFT quantum chemical calculations at the B3PW91/6-31G(d) level of theory have shown that the addition of secondary phosphine sulfides and phosphine selenides with alkyl, phenyl, and phenylalkyl substituents to pentyl vinyl and hexyl vinyl selenides follows a molecular mechanism against the Markovnikov rule through energetically favorable eight-membered transition state, leading to the formation of tertiary phosphine chalcogenides. Secondary phosphine selenides are more reactive than the corresponding phosphine sulfides. Keywords: phosphine sulfides, phosphine selenides, hydrophosphinylation, vinyl selenides, reaction mechanisms, DFT calculations
DOI: 10.1134/S1070428020100048 Interest in tertiary phosphine chalcogenides is determined by prospects of using them as ligands for metal complex catalysts and precursors to pharmaceuticals; in addition, they can be used for the preparation of selenium-containing nanoparticles [1–9]. Direct addition of P–H compounds to unsaturated carbon–carbon bonds in the presence of a base and metal catalyst or radical initiator in various organic solvents underlies a traditional method of C–P bond formation. In recent years, a new efficient protocol has been proposed for hydrophosphination and hydrophosphinylation of multiple carbon–carbon bonds with phosphines or phosphine chalcogenides in the absence of a catalyst, initiator, or solvent [10]. For example, a green atom-economical synthesis of tertiary phosphine sulfides and phosphine selenides has been developed on the basis of addition of secondary phosphine sulfides and phosphine selenides to a wide range of alkenes [such as heptene, cyclohexene, styrenes, allyl alcohol, vinyl ethers, vinyl sulfides, vinyl selenides, trimethyl(vinyl)silane, vinylimidazole, and vinyl acetate] without catalyst and solvent [11, 12]. The reactions were carried out at 80–82°C for 4–44 h, and the corresponding anti-Markovnikov adducts were formed with high chemo- and regioselectivity in good
to quantitative yields [11, 12]. Diphenylphosphine sulfide proved to be the most reactive, presumably due to low energy of dissociation of the P–H bond [11]. It was presumed that the above addition reaction follows a molecular mechanism involving six- or fourmembered transition state with concerted electron pair (or single elecetron) transfer without preliminary formation of ionic or radical species [12
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