Role of Additives to Overcome Limitations of Intermolecular Rhodium-Catalyzed Asymmetric Cyclopropanation

Jc, Sharland; Bian, Wei; Dj, Hardee; Tr, Hodges; Gong, William H.; Voight, Eric A.; Davies, Huw M. L.

doi:10.26434/chemrxiv.14479593.v1

Cited by 5 publications

(3 citation statements)

References 10 publications

(22 reference statements)

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“…Additives such as tetramethyl urea, Hünig's base, N,N-diethylaniline, 2,4,6trimethylpyridine, TfNH2, DMAP, and 2-chloropyridine also have been used to modulate the reactivity and selectivity of dirhodium tetracarboxylate complexes through axial coordination. [72][73][74][75][76]…”

Section: Axial Ligandsmentioning

confidence: 99%

Effects of Axial Solvent Coordination to Dirhodium Complexes on the Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

2021

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Density functional theory calculations were used to systematically explore the effects of axial ligation by solvent molecules on the reactivity and selectivity of dirhodium tetracarboxylates with diazo compounds in the context of C-H insertion into propane.Insertions on three types of diazo compounds-acceptor/acceptor, donor/acceptor, and donor/donor-promoted by dirhodium tetraformate were tested with and without axial solvent ligation for no surrounding solvent, dichloromethane, isopropanol, and acetonitrile. Magnitudes, origins, and consequences of structural and electronic changes arising from axial ligation were characterized. The results suggest that axial ligation affects barriers for N2 extrusion and C-H insertion, the former to a larger extent.

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Section: Axial Ligandsmentioning

confidence: 99%

Effects of Axial Solvent Coordination to Dirhodium Complexes on the Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

2021

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“…A moderate yield (64%) and enantioselectivity (71% ee) were observed. Previous studies have shown that addition of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) improved reaction performance in rhodium carbene-catalyzed reactions. − The addition of 20 equiv of HFIP to the semibatch reaction mixture resulted in an increased C–H insertion yield of 81% and a higher selectivity of 83% ee. Finally, we explored the performance of secondary C–H insertion using an unactivated substrate, in this case cyclohexane.…”

Section: Resultsmentioning

confidence: 99%

Copper-Catalyzed, Aerobic Oxidation of Hydrazone in a Three-Phase Packed Bed Reactor

Hatridge

Wei

Davies

et al. 2021

Org. Process Res. Dev.

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Copper-catalyzed, aerobic hydrazone oxidation to produce synthetically useful diazo compounds is achieved in a continuous, three-phase flow reactor with complete conversion and high selectivity by adapting a previously published batch methodology to a flow system described herein and conducting a parameter space exploration to optimize the process conditions. The robust nature of the process is demonstrated, with complete hydrazone conversion and a 90% steady-state diazo compound selectivity maintained over 11 residence times. Employing the diazo synthesis upstream of a limited scope of dirhodium(II)catalyzed carbene reactions demonstrates the utility of this process in generating on-demand diazo compounds for cycloaddition and activated secondary C−H insertion reactions. The resulting process represents, to the best of our knowledge, the first reported catalytic process for hydrazone oxidation in flow. Additionally, this process, which only generates water as an oxidative byproduct, is an improvement over previous noncatalytic attempts to synthesize diazo compounds in flow, which generate stoichiometric amounts of waste. The increased sustainability and mitigation of safety hazards associated with handling reactive diazo compounds may make this approach suitable for practical applications.

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Section: Axial Ligandsmentioning

confidence: 99%

Effects of Axial Solvent Coordination to Dirhodium Complexes on Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

Laconsay

Pla‐Quintana

Tantillo

2021

Preprint

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Density functional theory calculations were used to systematically explore the effects of axial ligation by solvent molecules on the reactivity and selectivity of dirhodium tetracarboxylates with diazo compounds in the context of C–H insertion into propane. Insertions on three types of diazo compounds—acceptor/acceptor, donor/acceptor, and donor/donor—promoted by dirhodium tetraformate were tested with and without axial solvent ligation for no surrounding solvent, dichloromethane, isopropanol, and acetonitrile. Magnitudes, origins, and consequences of structural and electronic changes arising from axial ligation were characterized. The results suggest that axial ligation affects barriers for N2 extrusion and C–H insertion, the former to a larger extent.

show abstract

Role of Additives to Overcome Limitations of Intermolecular Rhodium-Catalyzed Asymmetric Cyclopropanation

Cited by 5 publications

References 10 publications

Effects of Axial Solvent Coordination to Dirhodium Complexes on the Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

Effects of Axial Solvent Coordination to Dirhodium Complexes on the Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

Copper-Catalyzed, Aerobic Oxidation of Hydrazone in a Three-Phase Packed Bed Reactor

Effects of Axial Solvent Coordination to Dirhodium Complexes on Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study

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