title: Mechanisms and reactivity differences for the cobalt-catalyzed enantioselective intramolecular hydroacylation of ketones and alkenes: insights from density functional calculations.
abstract: Density functional theory (DFT) was used to study the cobalt(I)-catalyzed enantioselective intramolecular hydroacylation of ketones and alkenes. All intermediates and transition states were fully optimized at the M06/6-31G(d,p) level (LANL2DZ(f) for Co). The results demonstrated that the ketone and alkene present different reactivities in the enantioselective hydroacylation. In ketone hydroacylation catalyzed by the cobalt(I)-(R,R)-Ph-BPE complex, reaction channel "a" to (R)-phthalide was more favorable than channel "b" to (S)-phthalide. Hydrogen migration was both the rate-determining and chirality-limiting step, and this step was endothermic. In alkene hydroacylation catalyzed by the cobalt(I)-(R,R)-BDPP complex, reaction channel "c" leading to the formation of (S)-indanone was the most favorable, both thermodynamically and kinetically. Reductive elimination was the rate-determining step, but the chirality-limiting step was hydrogen migration, which occurred easily. The results also indicated that the alkene hydroacylation leading to (S)-indanone formation was more energetically favorable than the ketone hydroacylation that gave (R)-phthalide, both thermodynamically and kinetically.
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China. qingxim@sdau.edu.cn.
authors.forename: Qingxi
authors.initials: Q
authors.lastname: Meng
authors.affiliation: Department of Chemistry, Taishan University, Taian, Shandong, 271021, People's Republic of China.
authors.forename: Fen
authors.initials: F
authors.lastname: Wang
keywords: Alkene; Cobalt; DFT; Hydroacylation; Ketone