Recent Developments in Rhodium-Catalyzed Cyclocarbonylation Reactions

Burnie, Andrew J.; Evans, P. Andrew

doi:10.1007/3418_2016_169

Cited by 9 publications

(6 citation statements)

References 185 publications

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“…The Pauson–Khand reaction (PKR) is a go-to method for synthesizing cyclopentenones . Although there are several synthetic applications to demonstrate the highly diastereoselective nature of this reaction, an asymmetric PKR has been realized only once in total synthesis .…”

Section: Introductionmentioning

confidence: 99%

Mechanism and Origins of Enantioselectivity in the Rh(I)-Catalyzed Pauson–Khand Reaction: Comparison of Bidentate and Monodentate Chiral Ligands

et al. 2020

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The narrow substrate scope of the asymmetric Pauson–Khand reaction (PKR) presently limits its synthetic utility. We recently reported an example of an enantioselective PKR with a precursor not comprising a 1,6-enyne by using a cationic Rh(I) catalyst and a chiral monodentate phosphorous ligand. Herein, the mechanisms and ligand effects on the reactivity and selectivity of enyne PKRs using Rh(I) metal complexes with three different ligands ((R)-BINAP, (S)-MonoPhos, or CO) are examined experimentally and computationally. A correlation between experiments and DFT calculations is demonstrated. The PKR with the bidentate ligand (R)-BINAP is fast and shows a low calculated Gibbs free energy of activation (ΔG ‡) for the oxidative cyclization step; the monodentate ligand, (S)-MonoPhos, affords a much slower reaction with a higher ΔG ‡; and using the CO-only Rh complex, the reaction is very slow with a high ΔG ‡. A linear relationship between the enantiomeric excess of (S)-MonoPhos and the PKR product suggests that the active Rh catalyst involves a single ligand. The absolute configuration of the product afforded by each of these ligand-bound catalysts is determined by DFT calculations and confirmed by vibrational circular dichroism spectroscopy. Transition-state structures for the oxidative cyclization step show that the chiral induction is controlled by steric interactions between the phenyl groups of the (R)-BINAP ligand or the methyl groups of the (S)-MonoPhos ligand and an alkenyl hydrogen of the enyne. DFT calculations revealed two competing oxidative cyclization pathways involving either four- or five-coordinated Rh(I) species. The preferred mechanism and the enantioselectivity are affected by the ligand, the substrate, and CO concentration. Incorporating experimental temperature and CO concentration into the Gibbs free-energy calculations proved crucial for obtaining agreement with experimental results.

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Section: Introductionmentioning

confidence: 99%

Mechanism and Origins of Enantioselectivity in the Rh(I)-Catalyzed Pauson–Khand Reaction: Comparison of Bidentate and Monodentate Chiral Ligands

et al. 2020

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“…Pursuant to the discovery of the Pauson–Khand reaction (1973) and its intramolecular variants, , catalytic carbonylative (2+2+1) cycloadditions of alkynes and alkenes based on cobalt − and titanium − appeared in the 1990s. As described in the review literature, noble metal-catalyzed Pauson–Khand reactions, including enantioselective variants, soon followed. − In 1997, Murai and Mitsudo independently reported the first examples of ruthenium-catalyzed Pauson–Khand-type reactions (Scheme ). , Upon exposure to substoichiometric quantities of Ru 3 (CO) 12 under modest pressures of carbon monoxide (10–20 atm) at elevated temperatures (140–160 °C), 1,6-enynes are converted to the bicyclopentenones in high yields.…”

Section: Five-membered Ring Formationmentioning

confidence: 99%

Ruthenium-Catalyzed Cycloadditions to Form Five-, Six-, and Seven-Membered Rings

Doerksen

Hodík

et al. 2021

Chem. Rev.

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Ruthenium-catalyzed cycloadditions to form five-, six-, and seven-membered rings are summarized, including applications in natural product total synthesis. Content is organized by ring size and reaction type. Coverage is limited to processes that involve formation of at least one C–C bond. Processes that are stoichiometric in ruthenium or exploit ruthenium as a Lewis acid (without intervention of organometallic intermediates), ring formations that occur through dehydrogenative condensation-reduction, σ-bond activation-initiated annulations that do not result in net reduction of bond multiplicity, and photochemically promoted ruthenium-catalyzed cycloadditions are not covered.

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“…reaction between a VCP and a tethered alkyne (14), generating a fused 5,7-bicyclic system (15) via the general mechanism highlighted in Fig. 3.…”

Section: [5+2] Annulationsmentioning

confidence: 99%

Beyond geminal diesters: increasing the scope of metal-mediated vinylcyclopropane annulations while decreasing pre-activation

2018

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The utilization of unactivated substrates in annulation reactions provides access to complex products without the need for subsequent removal of the activating group. Vinylcyclopropanes (VCPs), occurring naturally in several monoterpene natural products, are an important building block for organic chemistry, and can be activated by electron withdrawing substituents directly on the cyclopropane to facilitate ring opening reactions. However, many VCPs that lack these activated groups remain reactive with several group 8, 9 and 10 transition metals, by alternative modes of activation, forming metallacycles. These useful intermediates produce annulation products in reactions with unsaturated π-units, providing rapid access to new carbocycles. Several formal cycloadditions that incorporate unactivated VCPs as substrates have been developed, including [5 + 2], [5 + 2 + 1], [5 + 1 + 2 + 1], [3 + 2], [3 + 2 + 1], [5 + 1], and others, using Rh, Ni, Ru, Ir, Fe and Co based catalysts. Mono- and polycyclic ring systems have been made using these methods with their utility demonstrated through the synthesis of complex natural products. This review will summarize the annulations of VCPs that lack geminal diesters, but retain reactivity via transition metal catalysts.

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Recent Developments in Rhodium-Catalyzed Cyclocarbonylation Reactions

Cited by 9 publications

References 185 publications

Mechanism and Origins of Enantioselectivity in the Rh(I)-Catalyzed Pauson–Khand Reaction: Comparison of Bidentate and Monodentate Chiral Ligands

Mechanism and Origins of Enantioselectivity in the Rh(I)-Catalyzed Pauson–Khand Reaction: Comparison of Bidentate and Monodentate Chiral Ligands

Ruthenium-Catalyzed Cycloadditions to Form Five-, Six-, and Seven-Membered Rings

Beyond geminal diesters: increasing the scope of metal-mediated vinylcyclopropane annulations while decreasing pre-activation

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