Stryker's reagent ([(PPh3)CuH]6),[1] also known as the Osborn complex, is a hexameric copper hydride ligated with triphenylphosphine. It is a brick red, air-sensitive solid. Stryker's reagent is a mildly hydridic reagent, used in homogeneous catalysis of conjugate reduction reactions of enones, enoates, and related substrates.
Stryker's Reagent [PPh3-CuH]6 under nitrogen atmosphere
The compound is prepared by adding sodium trimethoxyborohydride to a solution of [PPh3CuCl]4 in DMF, after which it precipitates out as a DMF complex ([HCu(PPh3)]6•DMF).[2] Other more convenient methods have been developed since its discovery.[3][4]
In terms of its structure, the compound is an octahedral cluster of Cu(PPh3) centres that are bonded by Cu---Cu and Cu---H interactions. Originally six of the eight faces were thought to be capped by hydride ligands.[5] This structural assignment was revised in 2014; the hydrides are now best described as edge bridging rather than face bridging.[6]
Applications in organic synthesisedit
The compound can effect regioselective conjugate reductions of various carbonyl derivatives including unsaturated aldehydes, ketones, and esters. This reagent was assigned as the "Reagent of the year" in 1991 for its functional group tolerance, high overall efficiency, and mild reaction conditions in the reduction reactions. Stryker's reagent is used in a catalytic amount where it is regenerated in the reaction in situ using a stoichiometric hydride source, often being molecular hydrogen or silanes. If stored under an inert atmosphere (e.g., argon, nitrogen) it has indefinite shelf life. Brief exposure to the oxygen does not destroy its activity significantly, although solvents used with Stryker's reagent should be rigorously degassed.[7]
Modifications to Stryker's reagentedit
Ligand-modified versions of Stryker's reagent have been reported. By changing the ligand to, e.g., P(O-iPr)3 the selectivity can be improved significantly.[8] In addition, Lipshutz et al., have shown that the addition of a bidentate, achiral bis-phosphine ligand on the Cu center can lead to substrate-to-ligand ratios typically on the order of 1000−10000:1 can be used to afford products in high yields.[9]
Referencesedit
^Mahoney, W.S.; Brestensky, D.M.; Stryker, J.M. (1988). "Selective Hydride-mediated conjugate reduction of α,β-unsaturated Carbonyl Compounds Using [(Ph3P)CuH]6". J. Am. Chem. Soc.110: 291–293. doi:10.1021/ja00209a048.
^Bezman, S. A.; Churchill, M. R.; Osborn, J. A.; Wormald, J. (1971). "Preparation and Crystallographic Characterization of a Hexameric Triphenylphosphinecopper Hydride Cluster". J. Am. Chem. Soc.93 (8): 2063–2065. doi:10.1021/ja00737a045.
^O. Riant "Copper(I) hydride reagents and catalysts" Patai's Chemistry of Functional Groups, 2011, John Wiley & Sons. doi:10.1002/9780470682531.pat0448
^R. D. Stephens "Hydrido(Triphenylphosphine)Copper(I)" Inorganic Syntheses, 1979, vol. 19, pp. 87–89. doi:10.1002/9780470132500.ch17
^Raymond C. Stevens, Malcolm R. McLean, Robert Bau, Thomas F. Koetzle "Neutron diffraction structure analysis of a hexanuclear copper hydrido complex, H6Cu6[P(p-tolyl)3]6: an unexpected finding" J. Am. Chem. Soc. 1989, pp 3472–3473. doi:10.1021/ja00191a077
^Bennett, Elliot L.; Murphy, Patrick J.; Imberti, Silvia; Parker, Stewart F. (2014-03-17). "Characterization of the Hydrides in Stryker's Reagent: [HCu{P(C6H5)3}]6". Inorganic Chemistry. 53 (6): 2963–2967. doi:10.1021/ic402736t. ISSN 0020-1669. PMID 24571368.
^John F. Daeuble and Jeffrey M. Stryker "Hexa-μ-hydrohexakis(triphenylphosphine)hexacopper" eEROS Encyclopedia of Reagents for Organic Synthesis, 2001. doi:10.1002/047084289X.rh011m
^Andrejs Pelss, Esa T. T. Kumpulainen and Ari M. P. Koskinen J. Org. Chem. 2009, 74, 7598-7601. [1]doi:10.1021/jo9017588
^Baker, Benjamin A.; Bošković, Žarko V.; Lipshutz, Bruce H. (2008). "(BDP)CuH: A "Hot" Stryker's Reagent for Use in Achiral Conjugate Reductions". Organic Letters. 10 (2): 289–292. doi:10.1021/ol702689v. PMID 18092793.
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December 15, 2023
stryker, reagent, pph3, also, known, osborn, complex, hexameric, copper, hydride, ligated, with, triphenylphosphine, brick, sensitive, solid, mildly, hydridic, reagent, used, homogeneous, catalysis, conjugate, reduction, reactions, enones, enoates, related, su. Stryker s reagent PPh3 CuH 6 1 also known as the Osborn complex is a hexameric copper hydride ligated with triphenylphosphine It is a brick red air sensitive solid Stryker s reagent is a mildly hydridic reagent used in homogeneous catalysis of conjugate reduction reactions of enones enoates and related substrates Stryker s reagent IdentifiersCAS Number 33636 93 0 Y3D model JSmol Interactive imageECHA InfoCard 100 156 010PubChem CID 12181933UNII 8X3R32M7XU YCompTox Dashboard EPA DTXSID40475132SMILES C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 C1 CC C C C1 P C2 CC CC C2 C3 CC CC C3 CuH CuH CuH CuH CuH CuH PropertiesChemical formula C108H96Cu6P6Molar mass 1961 04Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Preparation and structure 2 Applications in organic synthesis 3 Modifications to Stryker s reagent 4 ReferencesPreparation and structure edit nbsp Stryker s Reagent PPh3 CuH 6 under nitrogen atmosphereThe compound is prepared by adding sodium trimethoxyborohydride to a solution of PPh3CuCl 4 in DMF after which it precipitates out as a DMF complex HCu PPh3 6 DMF 2 Other more convenient methods have been developed since its discovery 3 4 In terms of its structure the compound is an octahedral cluster of Cu PPh3 centres that are bonded by Cu Cu and Cu H interactions Originally six of the eight faces were thought to be capped by hydride ligands 5 This structural assignment was revised in 2014 the hydrides are now best described as edge bridging rather than face bridging 6 Applications in organic synthesis editThe compound can effect regioselective conjugate reductions of various carbonyl derivatives including unsaturated aldehydes ketones and esters This reagent was assigned as the Reagent of the year in 1991 for its functional group tolerance high overall efficiency and mild reaction conditions in the reduction reactions Stryker s reagent is used in a catalytic amount where it is regenerated in the reaction in situ using a stoichiometric hydride source often being molecular hydrogen or silanes If stored under an inert atmosphere e g argon nitrogen it has indefinite shelf life Brief exposure to the oxygen does not destroy its activity significantly although solvents used with Stryker s reagent should be rigorously degassed 7 Modifications to Stryker s reagent editLigand modified versions of Stryker s reagent have been reported By changing the ligand to e g P O iPr 3 the selectivity can be improved significantly 8 In addition Lipshutz et al have shown that the addition of a bidentate achiral bis phosphine ligand on the Cu center can lead to substrate to ligand ratios typically on the order of 1000 10000 1 can be used to afford products in high yields 9 References edit Mahoney W S Brestensky D M Stryker J M 1988 Selective Hydride mediated conjugate reduction of a b unsaturated Carbonyl Compounds Using Ph3P CuH 6 J Am Chem Soc 110 291 293 doi 10 1021 ja00209a048 Bezman S A Churchill M R Osborn J A Wormald J 1971 Preparation and Crystallographic Characterization of a Hexameric Triphenylphosphinecopper Hydride Cluster J Am Chem Soc 93 8 2063 2065 doi 10 1021 ja00737a045 O Riant Copper I hydride reagents and catalysts Patai s Chemistry of Functional Groups 2011 John Wiley amp Sons doi 10 1002 9780470682531 pat0448 R D Stephens Hydrido Triphenylphosphine Copper I Inorganic Syntheses 1979 vol 19 pp 87 89 doi 10 1002 9780470132500 ch17 Raymond C Stevens Malcolm R McLean Robert Bau Thomas F Koetzle Neutron diffraction structure analysis of a hexanuclear copper hydrido complex H6Cu6 P p tolyl 3 6 an unexpected finding J Am Chem Soc 1989 pp 3472 3473 doi 10 1021 ja00191a077 Bennett Elliot L Murphy Patrick J Imberti Silvia Parker Stewart F 2014 03 17 Characterization of the Hydrides in Stryker s Reagent HCu P C6H5 3 6 Inorganic Chemistry 53 6 2963 2967 doi 10 1021 ic402736t ISSN 0020 1669 PMID 24571368 John F Daeuble and Jeffrey M Stryker Hexa m hydrohexakis triphenylphosphine hexacopper eEROS Encyclopedia of Reagents for Organic Synthesis 2001 doi 10 1002 047084289X rh011m Andrejs Pelss Esa T T Kumpulainen and Ari M P Koskinen J Org Chem 2009 74 7598 7601 1 doi 10 1021 jo9017588 Baker Benjamin A Boskovic Zarko V Lipshutz Bruce H 2008 BDP CuH A Hot Stryker s Reagent for Use in Achiral Conjugate Reductions Organic Letters 10 2 289 292 doi 10 1021 ol702689v PMID 18092793 nbsp Wikimedia Commons has media related to Stryker s reagent Retrieved from https en wikipedia org w index php title Stryker 27s reagent amp oldid 1178685507, wikipedia, wiki, book, books, library,
