Efficient reductions of dimethylhydrazones using preformed primary amine boranes

Frabitore, Christian; Lépeule, Jérome; Towey, Bradley; Livinghouse, Tom; Robinson, William C.

doi:10.1080/00397911.2021.2008449

Cited by 3 publications

(6 citation statements)

References 14 publications

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“…Diamine ligands can exert a stabilizing effect on copper catalysts [ 25 ]. These ligands also accelerate Cu(I)-catalyzed cross-coupling reactions [ 26 , 27 ]. Unfortunately, in our hands, the coupling of 2 with 1-bromo-2-phenylethyne in the presence of TMEDA (one equiv.)…”

Section: Resultsmentioning

confidence: 99%

“…Successful reactions with 1-bromo-2-phenylethyne took −76 °C to complete, and increasing the temperature inevitably led to decreased yiel Diamine ligands can exert a stabilizing effect on copper catalysts [25]. These ligan accelerate Cu(I)-catalyzed cross-coupling reactions [26,27]. Unfortunately, in our the coupling of 2 with 1-bromo-2-phenylethyne in the presence of TMEDA (one led to a marked decrease in the yield of 2b (25%).…”

Section: Resultsmentioning

confidence: 99%

“…All materials were either prepared according to previous literature or pur from commercial sources. N,N-dimethylhydrazinoalkene substrates 1-3 were sized by previously reported methods [11,27] and stored in an inert atmosphere glo All solvents were obtained from a JC Meyer solvent dispensing system. Inorgan were dried by heating under a high vacuum before use.…”

Section: Methodsmentioning

confidence: 99%

“…All materials were either prepared according to previous literature o from commercial sources. N,N-dimethylhydrazinoalkene substrates 1-3 w sized by previously reported methods [11,27] and stored in an inert atmosphe All solvents were obtained from a JC Meyer solvent dispensing system. In Knochel reported that Cu(I)-catalyzed cross-couplings with 1-bromo-2-pheny were difficult to control.…”

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents

2022

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Nitrogen-containing heterocycles represent the majority of FDA-approved small-molecule pharmaceuticals. Herein, we describe a synthetic method to produce saturated N-heterocyclic drug scaffolds with an internal alkyne for elaboration. The treatment of N,N-dimethylhydrazinoalkenes with Et2Zn, followed by a Cu(I)-catalyzed cross-coupling with 1-bromoalkynes, results in piperidines and pyrrolidines with a good yield. Five examples are reported and a proposed mechanism for the Cu(I)-catalyzed cross-coupling is presented.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents

2022

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“…Unexpectedly, the All materials were either prepared according to previous literature or purchased from commercial sources. N,N-Dimethylhydrazinoalkene substrates 1a-c were synthesized by previously reported methods 12,23 and stored in an inert atmosphere glovebox. All solvents were obtained from a JC Meyer solvent dispensing system.…”

Section: Figure 1 Nn-dimethylhydrazinoalkenes and 1-bromoalkynes Used...mentioning

confidence: 99%

On the Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents: Substrate Scope and Catalyst Evaluation

Livinghouse¹,

Frabitore²

2023

Synthesis

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Nitrogen-containing heterocycles are ubiquitous in FDA-approved small molecule pharmaceuticals. Herein, we expand on a novel synthetic method for the production of saturated N-heterocyclic pharmacophore motifs with an internal alkyne for elaboration. The treatment of N,N-dimethylhydrazinoalkenes with diethylzinc followed by a Cu(I)-catalyzed cross-coupling with 1-bromoalkynes affords piperidines and pyrrolidines in respectable yields. Functional group tolerance is demonstrated by the inclusion of heteroatom-bearing alkynes. Unexpectedly, the use of ethyl propiolate as the trapping electrophile led to selective N-functionalization with the formation of vinylogous urethanes. Alternative Cu(I) complexes were also evaluated as prospective catalysts. This synthetic protocol can readily be achieved on a preparative scale.

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Microwave‐Mediated Modification of Selected Limonoids with DMAB Reagent and Antibacterial Studies

Jayakumar,

Saxena,

Tomar

2024

Macromolecular Symposia

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N,N‐Dimethylaniline.borane (DMAB) is a stable, multifaceted electrophilic boron agent that displays hydroboration of C = C as well as selective reduction of functional groups under reflux, microwave, and ultrasound conditions. Natural products contain a plethora of functional groups that govern the specific bioactivity. It will be interesting to correlate the change in a functional group with the concern for change in bioactivity. Current research emphasizes the influence of microwave irradiation on moderately reactive DMAB reagent towards the functional group modification of selected limonoid‐phytochemicals of Meliaceae family viz. cedrelone, azadirone, nimbin, and azadiradione. DMAB conveniently reduces the ketone, epoxide group into alcohol, and does a hydroboration reaction on the C = C bond. It does not show interest to reduce the ester group irrespective of 30 min of MW irradiation. Except for these reducing properties, the reagent DMAB unveils chemo‐selective nature in respect of different functional groups and utilizes in an asymmetric synthesis. The coalescence of amine.borane with microwave irradiation brings forth a commodious and prompt method for the selective reduction of functional groups. The bioactive efficacy of modified phytochemicals is further taken for the antimicrobial studies.

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Efficient reductions of dimethylhydrazones using preformed primary amine boranes

Cited by 3 publications

References 14 publications

Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents

Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents

On the Copper(I)-Catalyzed Cross-Coupling of 1-Bromoalkynes with N-Heterocyclic Organozinc Reagents: Substrate Scope and Catalyst Evaluation

Microwave‐Mediated Modification of Selected Limonoids with DMAB Reagent and Antibacterial Studies

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