Ruthenium-Catalyzed Transfer Hydrogenation for C–C Bond Formation: Hydrohydroxyalkylation and Hydroaminoalkylation via Reactant Redox Pairs

Perez, Felix; Oda, Susumu; Geary, Laina M.; Krische, Michael J.

doi:10.1007/978-3-319-43051-5_8

Cited by 21 publications

(11 citation statements)

References 88 publications

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“…Several metals across the periodic table can be used for this transformation. ,,− An early contribution showed using deuterium labeling studies that early transition metal complexes are proposed to catalyze this reaction via a metallaziridine intermediate (Scheme ). Such catalytically active species are then proposed to proceed through alkene insertion to form the new C–C bond.…”

Section: Introductionmentioning

confidence: 99%

Ta-Catalyzed Hydroaminoalkylation of Alkenes: Insights into Ligand-Modified Reactivity Using DFT

et al. 2018

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Density functional theory (DFT) calculations were performed to probe the mechanism of tantalum-catalyzed hydroaminoalkylation, a reaction that affords Csp3–Csp3 bond formation via α-alkylation of a secondary amine with an alkene. Electronic effects in catalyst design were probed to reveal key features in the energy profile of the proposed mechanism, corroborating experimental trends in which electrophilic metal centers demonstrate enhanced reactivity. Modeling of the energy profile with an N,O-chelating amidate Ta catalyst (I) revealed profound differences in relative energetics, rationalizing improvements that have been observed using sterically and electronically varied ligands. N,O-Chelating ligands electronically promote preferential reactivity in the equatorial plane. The turnover-limiting step can be completely changed depending upon the ligand; for sterically bulky monoamidate complexes, the protonolysis of an intermediate metallacycle is the turnover-limiting step rather than C–H activation, as has been found for systems lacking steric bulk. Unproductive off-cycle pathways were also modeled to compare with experimental studies. These insights contribute to a theoretical understanding of key features in ligand design for developing improved catalysts for hydroaminoalkylation.

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Section: Introductionmentioning

confidence: 99%

Ta-Catalyzed Hydroaminoalkylation of Alkenes: Insights into Ligand-Modified Reactivity Using DFT

et al. 2018

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“…7–13 These processes offer an alternative to the use of stoichiometric carbanions in a range of classical carbonyl additions, bypassing the issues of safety, selectivity and waste generation posed by premetalated reagents. Of potentially greater importance, the new patterns of reactivity underlying the present hydrogen-mediated C–C bond formations are empowering processes beyond classical transformations, unlocking hitherto unavailable volumes of chemical space.…”

Section: Resultsmentioning

confidence: 99%

Reductive C–C coupling via hydrogenation and transfer hydrogenation: Departure from stoichiometric metals in carbonyl addition

Roane

Holmes

Krische

2017

Current Opinion in Green and Sustainable Chemistry

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“…Also highlighted is the precise chemoselectivity that this method entails as demonstrated through the enantioselective allylation at the site of a single alcohol in a polyol without the need for protecting groups . Progress has also been made by employing other metal catalysts in this method, specifically ruthenium, while maintaining the reactivity profile of the iridium catalysts in the allylation reactions of allenes and dienes with aldehydes. − In an impressive illustration of the utility of the transfer hydrogenation methodology, Krische synthesized the natural product swinholide A in only 15 steps (longest linear sequence), as compared to previous syntheses which required 27–35 steps . This accomplishment is possible because of the greatly increased “redox-economy” that is allowed through the use of transfer hydrogenation as many traditional redox and C–C bond formations steps can be combined into a single step.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Nucleophilic Allylation Driven by the Water–Gas Shift Reaction

et al. 2017

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The ruthenium-catalyzed allylation of aldehydes with allylic pro-nucleophiles has been demonstrated to be an efficient means to form carbon–carbon bonds under mild conditions. The evolution of this reaction from the initial serendipitous discovery to its general synthetic scope is detailed, highlighting the roles of water, CO, and amine in the generation of a more complete catalytic cycle. The use of unsymmetrical allylic pro-nucleophiles was shown to give preferential product formation through the modulation of reaction conditions. Both (E)-cinnamyl acetate and vinyl oxirane were efficiently used to form the anti-branched products (up to >20:1 anti/syn) and E-linear products (up to >20:1 E/Z) in high selectivity with aromatic, α,β-unsaturated, and aliphatic aldehydes, respectively. Attempts to render the reaction enantioselective are highlighted and include enantioenrichment of up to 75:25 for benzaldehyde.

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Ruthenium-Catalyzed Transfer Hydrogenation for C–C Bond Formation: Hydrohydroxyalkylation and Hydroaminoalkylation via Reactant Redox Pairs

Cited by 21 publications

References 88 publications

Ta-Catalyzed Hydroaminoalkylation of Alkenes: Insights into Ligand-Modified Reactivity Using DFT

Ta-Catalyzed Hydroaminoalkylation of Alkenes: Insights into Ligand-Modified Reactivity Using DFT

Reductive C–C coupling via hydrogenation and transfer hydrogenation: Departure from stoichiometric metals in carbonyl addition

Catalytic Nucleophilic Allylation Driven by the Water–Gas Shift Reaction

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