Efficient Synthesis of Alkyl β-Diketimines

Bradley, Alexander Z.; Thorn, David L.; Glover, Gerald V.

doi:10.1021/jo801691m

Cited by 17 publications

(15 citation statements)

References 8 publications

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“…N , N '-Dibenzyl-β-diketimine, 1 , or other diketimine ligands with aliphatic N-substituents have previously been prepared employing O-alkylation of the monocondensation product or the ethylene glycol monoketal of acetylacetone . We obtained 1 in high yields of 80% by direct condensation of benzylamine and acetylacetone in the presence of 1 equiv of acid .…”

Section: Resultsmentioning

confidence: 99%

π Back-Bonding in Dibenzyl-β-diketiminato Copper Olefin Complexes

Oguadinma

Schaper

2009

Organometallics

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N,N'-Dibenzyl-4-amino-2-iminopent-3-ene, nacnac Bn H, was obtained in a one-step synthesis starting from benzylamine and acetylacetone. Reaction of nacnac Bn H with CuOtBu in the presence of various Lewis bases gave the corresponding copper complexes (nacnac Bn )CuL (L: 2, styrene; 3, η 2acrylonitrile; 4, allyl phenyl ether; 5, stilbene; 7, xylylisonitrile; 8, triphenylphosphine). With diphenylacetylene (DPA) the dimeric complex {(nacnac Bn )Cu} 2 (μ-DPA), 6, was obtained. In the presence of excess DPA, 6 coordinates additional acetylene to form the monomeric complex (nacnac Bn )Cu(DPA), 6b. All complexes, with the exception of 4 and 6b, were characterized by X-ray diffraction studies. Structural and spectroscopic data indicate that π back-bonding in 2-8 is still weak when compared to other transition metals, but stronger than in most Cu(I) complexes. Olefin exchange experiments indicate preferred binding of electron-deficient olefins. Reaction of 3 with morpholine did not yield any hydroamination products, in agreement with significant π backbonding toward the olefin.

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Section: Resultsmentioning

confidence: 99%

π Back-Bonding in Dibenzyl-β-diketiminato Copper Olefin Complexes

Oguadinma

Schaper

2009

Organometallics

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“…NMR spectra were recorded on a Bruker ARX 400 MHz spectrometer and referenced to residual solvent (C 6 D 5 H: d 7.15, C 6 D 6 : d 128.02) or external reference ( 31 P, 75% H 3 PO 4 ). nacnac i-Pr H (1) 14, 15 Acetylacetone (4.0 mL, 38 mmol), para-toluenesulfonic acid monohydrate (7.2 g, 38 mmol), and isopropylamine (6.1 mL, 76 mmol) were added to toluene (200 mL) and refluxed with the help of a Dean-Stark apparatus for 5 days, during which the yellow suspension turned brown. After cooling to room temperature, the brown precipitate formed was filtered.…”

Section: Methodsmentioning

confidence: 99%

“…Ligand 1 has been obtained previously by a multi-step protocol, which is generally used to prepare N-alkyl diketiminates, either by employing Meerwein salt (32%-60% yield) 14 or dimethylsulfate (74% yield, from the aminoketone) 15 as O-alkylating agents. We employed a one-step procedure for condensation of acetylacetone with isopropylamine in the presence of equimolar amounts of para-toluenesulfonic acid, 16 which afforded 1 directly, albeit in a relatively low yield of 23% after 5 days of reflux (Scheme 1).…”

Section: Ligand and Complex Synthesismentioning

confidence: 99%

Synthesis and structures of isopropyl-β-diketiminato copper(I) complexes

Oguadinma

Schaper

2010

Can. J. Chem.

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The reaction of N,N'-diisopropyl-2-amino-4-iminopent-2-ene (nacnac i-Pr H, 1) either with CuOt-Bu or with a mixture of mesityl copper and 10% CuOt-Bu afforded, in the presence of PPh 3 , CN(C 6 Me 2 H 3 ), or MeCN, the Lewis base coordinated complexes nacnac i-Pr CuPPh3Á0.5 C6H14 (2), nacnac i-Pr CuCN(C6Me2H3) (3), and nacnac i-Pr Cu(NCMe) (4). Compounds 2, 3, and 4 were characterized by single-crystal X-ray diffraction studies. Compound 4 afforded two species in deuterated benzene in a 2:1 ratio, which were assigned to {nacnac i-Pr Cu}2(m-NCMe) and nacnac i-Pr CuNCMe (4). Upon addition of 5 equiv. of MeCN, the two sets collapsed into that of 4. No copper complexes were formed in the presence of styrene, stilbene, or diphenylacetylene.

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“…Much like β‐diketones and β‐enaminones, closely related isoelectronic and isostructural β‐enaminoimines have also received increasing attention, which stems from the scope for variation of the substituents on the backbone (β‐C) or nitrogen atoms . Thus, depending on the attached substituents, the possible number of isomeric or tautomeric forms of β‐enaminoimines increases in comparison with β‐diketones and β‐enaminones (Scheme ).…”

Section: Rahb As a Driving Force In Synthesismentioning

confidence: 99%

Resonance‐Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials

Mahmudov

Pombeiro

2016

Chemistry A European J

145

100

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Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.

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Efficient Synthesis of Alkyl β-Diketimines

Abstract: A general synthesis for the preparation of alkyl N,N'-beta-diketimines has been developed. The method reported here demonstrates the use of dimethyl sulfate for conversion of enaminoketones to beta-diketimines. The reaction can be performed without solvent, providing good yields.

Cited by 17 publications

References 8 publications

π Back-Bonding in Dibenzyl-β-diketiminato Copper Olefin Complexes

π Back-Bonding in Dibenzyl-β-diketiminato Copper Olefin Complexes

Synthesis and structures of isopropyl-β-diketiminato copper(I) complexes

Resonance‐Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials

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