Modifying Alkylzinc Reactivity with 2,2′‐Dipyridylamide: Activation of <i>t</i>BuZn Bonds for <i>para</i>‐Alkylation of Benzophenone

Armstrong, David R.; Garden, Jennifer A.; Kennedy, Alan R.; Mulvey, Robert E.; Robertson, Stuart D.

doi:10.1002/anie.201302426

Cited by 24 publications

(14 citation statements)

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“…A closer look into the structures of 2b-S 4 , 2h-S 3 and 2i-S 2 shows that along with the steric demands of the amide, electronic effects can also play a role in the degree of solvation. Thus, in centrosymmetric 2i-S 2 , multidentate 2,2′-bipyridylamide ligands adopt a syn – syn conformation, 29 with two N (amido) bridges connecting the Li centers, with each ligand forming two additional dative N (pyridyl)–Li interactions. In contrast with diphenylamide derivative 2h-S 3 , here the higher hapticity of the amide group favours the formation of a disolvated dimer, with only one molecule of 2-MeTHF coordinated per Li atom.…”

Section: Resultsmentioning

confidence: 99%

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Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents

et al. 2020

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Section: Resultsmentioning

confidence: 99%

“…27 a 2-MeTHF: molecular weights derived from 1 H DOSY-ICC-MW determinations at 0.2 M concentrations in 0.5 mL 2-MeTHF with 1,2,3,4-tetraphenylnaphthalene (TPhN), 1-phenylnaphthalene (1-PhN) and TMS as internal reference standards. 29 See the ESI for full details.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents

et al. 2020

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“…In addition, the bridging DPA ligands in 4 effectively mirror one another by significant twisting of the pyridyl rings from the {Na1-N2-Fe1-N5} core plane, maximising Npyridyl coordination to both metal centres (Fig. 6) 54 In the former structure, one DPA bridges syn/syn between two Na atoms and another bridges in anti/anti conformation with Namido centred between the Na atoms and the pyridyl N atoms coordinating to Zn. In contrast, the latter solvent-separated ion pair, has a single unit of DPA sandwiched between two Zn centres in an anti/anti conformation.…”

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confidence: 99%

“…54 Being the simplest of the DPA through three N sites; one central amido N and two neutral pyridyl N atoms. 55 Rotation around the two Namido-C bonds allows for DPA to adopt three different conformations; syn/syn, syn/anti and anti/anti (Fig.…”

Section: Introductionmentioning

confidence: 99%

Synthetic, structural and magnetic implications of introducing 2,2′-dipyridylamide to sodium-ferrate complexes

et al. 2017

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This version is available at https://strathprints.strath.ac.uk/60604/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. Using a transamination approach to access novel Fe(II) complexes, this study presents the synthesis, X-ray crystallographic and magnetic characterisation of a series of new iron complexes containing the multifunctional 2,2-dipyridylamide (DPA) ligand using iron bis(amide) [{Fe(HMDS)2}2] and sodium ferrate [{NaFe(HMDS)3} ] (1) as precursors (HMDS = 1,1,1,3,3,3hexamethyldisilazide). Reactions of DPA(H) with 1 show exceptionally good stoichiometric control, allowing access to heteroleptic [(THF)2·NaFe(DPA)(HMDS)2] (3) and homoleptic [{THF·NaFe(DPA)3} ] (4) by using 1 and 3 equivalents of DPA(H) respectively. Linking this methodology and co-complexation, which is a more widely used approach to prepare heterobimetallic complexes, 3 can also be prepared by combining NaHMDS with heteroleptic [{Fe(DPA)(HMDS)}2] (2). In turn, 2 has been also synthesised and structurally defined by reacting [{Fe(HMDS)2}2] with two equivalents of DPA(H). Structural studies demonstrate the coordination flexibility of the N-bridged bis(heterocycle) ligand DPA, with 2 and 3 exhibiting discrete monomeric motifs, whereas 4 displays a much more intricate supramolecular structure, with one of its DPA ligands coordinating in an anti/anti fashion (as opposed to 2 and 3 where DPA shows a syn/syn conformation), which facilitates propagation of the structure via its central amido N. Magnetic studies confirmed the high-spin electron configuration of the iron(II) centres in all three compounds and revealed the existence of weak ferromagnetic interactions in dinuclear compound 2 (J = 1.01 cm -1 ). Journal Name ARTICLE

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“…This solubility,w hichw as attributed to the steric effect of the tertbutyl arm alpha to the NÀLi bond and itsc onsequentm olecular constitution since in contrast the n-butyl isomer 2-nBuC 5 H 5 NLi (1n)i sahexane-insoluble polymer,m akes it an excellent LiH surrogate complex, as exemplified by its hydrolithiationo fb enzophenone. [22] Practical soluble sources of alkali-metal hydrides are covetedw ith only as elect few examples reported. [23] Furthermore, it was possible to characterize this 1,2-dihydropyridyl complexc rystallographically as am onomer,p resumably am ore reactive form than an aggregated type, by coordinatively saturating the lithium with ap olydentate neutral donor in 2-tBuC 5 H 5 NLi·Me 6 TREN, 1t·Me 6 TREN.…”

Section: Introductionmentioning

confidence: 99%

Developing Lithium Chemistry of 1,2‐Dihydropyridines: From Kinetic Intermediates to Isolable Characterized Compounds

Armstrong

Harris

Kennedy

et al. 2015

Chemistry A European J

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Generally considered kinetic intermediates in addition reactions of alkyllithiums to pyridine, 1-lithio-2-alkyl-1,2-dihydropyridines have been rarely isolated or characterized. This study develops their "isolated" chemistry. By a unique stoichiometric (that is, 1:1, alkyllithium/pyridine ratios) synthetic approach using tridentate donors we show it is possible to stabilize and hence crystallize monomeric complexes where alkyl is tert-butyl. Theoretical calculations probing the donor-free parent tert-butyl species reveal 12 energetically similar stereoisomers in two distinct cyclotrimeric (LiN)3 conformations. NMR spectroscopy studies (including DOSY spectra) and thermal volatility analysis compare new sec-butyl and iso-butyl isomers showing the former is a hexane soluble efficient hydrolithiation agent converting benzophenone to lithium diphenylmethoxide. Emphasizing the criticalness of stoichiometry, reaction of nBuLi/Me6 TREN with two equivalents of pyridine results in non-alkylated 1-lithio-1,4-dihydropyridine⋅Me6 TREN and 2-n-butylpyridine, implying mechanistically the kinetic 1,2-n-butyl intermediate hydrolithiates the second pyridine.

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Modifying Alkylzinc Reactivity with 2,2′‐Dipyridylamide: Activation of tBuZn Bonds for para‐Alkylation of Benzophenone

Cited by 24 publications

References 37 publications

Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents

Ultrafast amidation of esters using lithium amides under aerobic ambient temperature conditions in sustainable solvents

Synthetic, structural and magnetic implications of introducing 2,2′-dipyridylamide to sodium-ferrate complexes

Developing Lithium Chemistry of 1,2‐Dihydropyridines: From Kinetic Intermediates to Isolable Characterized Compounds

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