Facile homogeneous hydrogenations of hindered olefins with [Ir(cod)py(PCy3)]PF6

Suggs, J. William; Cox, S. D.; Crabtree, Robert H.; Quirk, Jennifer M.

doi:10.1016/0040-4039(81)80081-0

Cited by 69 publications

(28 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[7b, 20] Therefore, we carried out the catalytic hydrogenation by using various catalysts (Pd/ C, PtO 2 or [Ir(cod)py(PCy 3 )]PF 6 (Crabtree catalyst [21] ); cod cyclooctadiene, py pyridine) and solvents (AcOEt, AcOEt mixed with EtOH and H 2 O or amines, AcOH). In all cases, we obtained mixtures of royleanone (1) and its C-5 epimer; the best result was achieved working with H 2 at atmospheric pressure in the presence of Pd/C and in a 1:1 mixture of AcOEt:AcOH.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (+)-Royleanone from Sulfinyl Quinones

Carreño¹,

Ruano²,

Toledo³

2000

Chem. Eur. J.

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (+)-Royleanone from Sulfinyl Quinones

Carreño¹,

Ruano²,

Toledo³

2000

Chem. Eur. J.

View full text Add to dashboard Cite

show abstract

“…The unreactivity of trisubstituted alkenes towards rhodium complexes is overcome by increasing the hydrogen pressure, and the selectivity is comparable to (or a little better than) that obtained with iridium catalysts under atmospheric pressure [5]. The results of the hydrogenation of alkenes with lanthanide, ruthenium and iridium catalysts are listed in Table 21.1 [6][7][8]. In these reductions, the catalyst approaches the face of the double bond from the less-hindered side, and selection of the diastereoface of the substrate is straightforward when the stereogenic center is disposed adjacent to the double bond [6].…”

Section: Introductionmentioning

confidence: 99%

“…In these reductions, the catalyst approaches the face of the double bond from the less-hindered side, and selection of the diastereoface of the substrate is straightforward when the stereogenic center is disposed adjacent to the double bond [6]. In the hydrogenation of double bonds in steroidal compounds, diastereoselectivity induced by iridium catalysts is very high [8]. In the reduction of dehydroamino acid derivatives with a chiral unit, an achiral rhodium catalyst resulted in stereorandom products (Table 21.1, entries 9 and 10) [9].…”

Section: Introductionmentioning

confidence: 99%

Diastereoselective Hydrogenation

Yamagishi¹

2006

The Handbook of Homogeneous Hydrogenation

View full text Add to dashboard Cite

show abstract

“…On the basis of a suggestion made by Bill Suggs, the catalyst was used for more appropriate substrates, and the results obtained published [8]. More importantly, based on a further suggestion by Sarah Danishevsky, strong (99%) directing effects were also found in which the catalyst binds to a substrate OH or C=O group and then delivers H 2 almost exclusively from the face of the substrate that contains the binding group [9].…”

mentioning

confidence: 99%

Iridium

Crabtree¹

2006

The Handbook of Homogeneous Hydrogenation

Self Cite

View full text Add to dashboard Cite

Today, iridium compounds find so many varied applications in contemporary homogeneous catalysis it is difficult to recall that, until the late 1970s, rhodium was one of only two metals considered likely to serve as useful catalysts, at that time typically for hydrogenation or hydroformylation. Indeed, catalyst/solvent combinations such as [IrCl(PPh 3 ) 3 ]/MeOH, which were modeled directly on what was previously successful for rhodium, failed for iridium. Although iridium was still considered potentially to be useful, this was only for the demonstration of stoichiometric reactions related to proposed catalytic cycles. Iridium tends to form stronger metal-ligand bonds (e.g., Cp(CO)Rh-CO, 46 kcal mol -1 ; Cp(CO)Ir-CO, 57 kcal mol -1 ), and consequently compounds which act as reactive intermediates for rhodium can sometimes be isolated in the case of iridium.When low-coordinate iridium fragments in "non-coordinating" solvents (e.g., {Ir(PPh 3 ) 2 } + in CH 2 Cl 2 ) were found to be much more active than their rhodium analogues, it became clear that it is the dissociation of ligands or solvent -much slower for Ir versus Rh and for MeOH versus CH 2 Cl 2 -that leads to low catalytic rates with [IrCl(PPh 3 ) 3 ]/MeOH. The other steps in the catalytic cycle are often very fast for Ir, so if the need for dissociation is avoided, then highly active Ir catalysts can be formed. However, a new consensus has now emerged: rhodium catalysts are often considered to be slower but more selective, whilst iridium catalysts are faster but less selective. Historical AspectsIridium made its first major mark in 1965, in the arena of organometallic chemistry with the discovery of Vaska's complex, [IrCl(CO)(PPh 3 ) 2 ] (1) [1]. Only weakly catalytic itself, Vaska's complex is nevertheless highly relevant to cataly- 31The Handbook of Homogeneous Hydrogenation. Edited by J. G. de Vries and C. J. Elsevier

show abstract

Facile homogeneous hydrogenations of hindered olefins with [Ir(cod)py(PCy3)]PF6

Cited by 69 publications

References 5 publications

Enantioselective Synthesis of (+)-Royleanone from Sulfinyl Quinones

Enantioselective Synthesis of (+)-Royleanone from Sulfinyl Quinones

Diastereoselective Hydrogenation

Iridium

Contact Info

Product

Resources

About