1stGeneration Hoveyda Catalyst1 (PCy3 = tricyclohexylphosphine) – CAS#: [203714-71-0] – FW: 600.61 – Color: Brown – Initiation temperature: >0 °C Process Strengths Weaknesses CM2 -Synthesis of 1,2-disubstituted olefins from terminal olefins -Ethenolysis of internal olefins to make terminal olefins -Formation of trisubstituted olefins -Electron-deficient substrates-Hindered substrates RCM -Synthesis of 1,2-disubstituted olefins -Typically forms the kinetic […]
Fast-initiating Grubbs Catalyst
Fast-initiating Grubbs Catalyst1 (Ph = phenyl; Mes = mesityl) – CAS#: [900169-53-1] – FW: 884 – Color: Green – Initiation temperature: <0 °C Process Strengths Weaknesses CM2 -Efficient CM w/ acrylonitrile -Poor thermal stability in solution RCM -Activates at low temperatures ROMP -Provides narrow polydispersity materials -Will create a rapid exotherm w/ strained olefin […]
2nd Generation Hoveyda Catalyst
2ndGeneration Hoveyda Catalyst1 – CAS#: [301224-40-8] – FW: 626.62 – Color: Green – Initiation temperature: >0 °C Process Strengths Weaknesses CM2 -Compatible with most olefins, including highly electron-deficient (i.e. acrylonitrile) -Incompatible with hindered substrates RCM -Forms di- and trisubstituted olefins rapidly (5- & 6-membered rings) -Excels at macrocycle formation -Tetrasubstituted olefin formation is slow and […]
2nd Generation Grubbs Catalyst
2nd Generation Grubbs Catalyst1 (Ph = phenyl; PCy3 = tricyclohexylphosphine) – CAS#: [246047-72-3] – FW: 848.97 – Color: Orange-brown – Initiation temperature: >10 °C. Process Strengths Weaknesses CM2 -Applies to most olefins -Deactivated olefins (e.g. vinyl phosphonates, α, β-unsaturated carbonyls) -Typically forms the thermodynamic E/Z ratio -Highly electron-deficient substrates -Very Hindered substrates RCM -Synthesis of […]
1st Generation Grubbs Catalyst
1st Generation Grubbs Catalyst1 (Ph = phenyl; PCy3 = tricyclohexylphosphine) – CAS#: [172222-30-9] – FW: 822.95 – Color: Purple – Initiation temperature: >20 °C Process Strengths Weaknesses CM2 -Synthesis of 1,2-disubstituted olefins from terminal olefins-Ethenolysis of internal olefins to make terminal olefins-ADMET of unhindered terminal olefins -Formation of trisubstituted olefins-Electron-deficient substrates-Hindered substrates RCM -Synthesis of […]
Ruthenium Catalysts – 2nd Generation
The second revolution in ruthenium-catalyzed olefin metathesis was triggered by substituting one phosphine ligand in 1st generation catalysts with a more basic N-heterocyclic carbene (NHC). The activity of these 2nd generation (NHC-bearing) catalysts superseded that of 1st generation while maintaining functional group tolerance. The 2nd generation Grubbs catalyst (I) is undoubtedly the most well-known example […]
Ruthenium Catalysts – 1st Generation
Modern ruthenium based olefin catalysts encompass a range of complexes able to readily generate a 14 electron catalytic active species of the generic formula (L)(X2)Ru=CRR’ (L being a phosphine ligand in first generation catalysts). The first well-defined catalysts of this type, discovered by Grubbs in the early 90’s, feature a ruthenium metal center flanked with […]