Stereoselective iron-catalyzed alkyne hydrogenation in ionic liquids

Abstract

Iron(0) nanoparticles in ionic liquids (ILs) have been shown to catalyse the semi-hydrogenation of alkynes. In the presence of a nitrile-functionalised IL or acetonitrile, stereoselective formation of (Z)-alkenes was observed. The biphasic solvent system allowed facile separation and re-use of the catalyst.

Bimetallic Pt/Sn‐based Nanoparticles in Ionic Liquids as Nanocatalysts for the Selective Hydrogenation of Cinnamaldehyde

“…The IL as a tunable catalyst component gives also rise to catalysts with improved selectivity. Metal nanoparticles (e.g., Pd, Ni, Fe), for example, which were stabilized in nitrile‐functionalized ILs or acetonitrile/IL mixtures, were demonstrated to selectively hydrogenate alkynes to Z‐alkenes , , . Pt@IL nanoparticles with a chinchonidine costabilizer were further employed for the enantioselective hydrogenation of methyl benzoyl formate …”

“…were stabilized in nitrile-functionalized ILs or acetonitrile/IL mixtures, were demonstrated to selectively hydrogenate alkynes to Z-alkenes. [6,7,8] Pt@IL nanoparticles with a chinchonidine costabilizer were further employed for the enantioselective hydrogenation of methyl benzoyl formate. [9] The synthesis of heterometallic particles (e.g., random alloys, intermetallic compounds, or core-shell-type systems) adds another dimension for tuning the catalytic properties.…”

Facile Light‐Mediated Preparation of Small Polymer‐Coated Palladium‐Nanoparticles and Their Application as Catalysts for Alkyne Semi‐Hydrogenation

“…[2] Different inorganic (for example, CeO 2 ,T iO 2 ,C u 2 O, SiO 2 )o rorganic materials (ionic liquids, polymers, surfactants) have been used as supports for these transition-metal nanocatalysts. [2] Importantly,t hese novel hybridsm ay replace the well-established Lindlar catalyst in future.I ti sw ell known that the Lindlarc atalyst suffers from an umber of drawbacks:f irst, toxic Pb(OAc) 2 and large amountso fq uinoline are required as catalyst poison to suppress over-hydrogenationo ft he targeteda lkenest ot he corresponding alkanes. Second, reactions run with the Lindlar catalyst often show problems with respectt oZ/E-isomerization, over-hydrogenation,i rreproducibility,a nd al imited substrate scope.…”

“…[1] For instance, Pd, Fe, Ni, or Au nanocatalysts have been successfully appliedtothe selective semi-hydrogenation of terminal and internal alkynes,u sing for example H 2 ,a mmonium formate, or amine-borane complexesa sr eductants. [2] Different inorganic (for example, CeO 2 ,T iO 2 ,C u 2 O, SiO 2 )o rorganic materials (ionic liquids, polymers, surfactants) have been used as supports for these transition-metal nanocatalysts. [2] Importantly,t hese novel hybridsm ay replace the well-established Lindlar catalyst in future.I ti sw ell known that the Lindlarc atalyst suffers from an umber of drawbacks:f irst, toxic Pb(OAc) 2 and large amountso fq uinoline are required as catalyst poison to suppress over-hydrogenationo ft he targeteda lkenest ot he corresponding alkanes.…”

“…recently reported as imple PdNP/nanomicelle systemf or semi-hydrogenation of alkynest oZ-alkenes in water. [2j] The PdNP/nanomicelle catalystc harged with H 2 was elegantly prepared in situ by addition of NaBH 4 and Pd(OAc) 2 to an aqueous solution of nanomicelles made from the commerciallya vailable surfactantT PGS-750-M. The Lipshutz catalyst provided high yields of Z-alkenesa nd could be successfully recycled severalt imes.…”