Understanding asymmetric hydrogenation of alkenes catalyzed by the first-row transition metal Fe: a first-principles
Akhilesh Mahato1, Anupama Mahato1, Sourav Ghoshal2
1Department of Chemistry, Sidho-Kanho-Birsha University, Purulia, West Bengal-723104, India. anup.pramanik@skbu.ac.in.
Abstract:
First-principles analyses were performed for understanding the mechanistic details of Fe-catalysed asymmetric hydrogenation of alkenes in the presence of silane that has recently been experimentally realized. The catalytic hydrogenation is expected to proceed through initial hydride transfer from Fe-H to the CC bond of alkene, followed by σ-bond metathesis of hydrosilane to afford a chiral alkane product and an iron silyl species, which then reacts with H2 to regenerate the iron hydride species via another σ-bond metathesis. The mechanistic details and the origin of the regioselectivity and stereoselectivity of these reactions are understood on the basis of detailed potential energy surface analysis, charge transfer and noncovalent interactions involved therein, strain energy and isodesmic studies in the solvated stage. Finally, general aspects are highlighted for guiding further experimental studies to precisely control the reaction scheme.
Related Concept Videos
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
02:13Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
01:28Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation