Orthosilicate-Mediated Esterification of Monosubstituted Phosphinic Acids

Dumond, Yves; Baker, R.; Montchamp, Jean‐Luc

doi:10.1021/ol006434g

Cited by 55 publications

(37 citation statements)

References 26 publications

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“…At the outset, cross-coupling reactions of H-phosphinate 2a 15 with phenyl iodide 1a were examined in the presence of nickel complexes under several conditions (Table 1). Upon treatment of 1a with 2a in the presence of NiCl 2 $6H 2 O (10 mol %), 2,2 0 -bipyridine (bipy) (20 mol %), and zinc (2 equiv) as an additive using water solvent at 70 C, according to Tang's conditions, 12 the desired product 3a was obtained in only 8% yield (entry 1).…”

Section: Resultsmentioning

confidence: 99%

Nickel-catalyzed C–P cross-coupling reactions of aryl iodides with H-phosphinates

et al. 2015

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Section: Resultsmentioning

confidence: 99%

Nickel-catalyzed C–P cross-coupling reactions of aryl iodides with H-phosphinates

et al. 2015

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“…Initially, we reported the selective esterification of H-phosphinic acids in the presence of dialkyl phosphinic acids using alkoxysilanes (Eq. (1)) [8]. This reaction is useful when a particular method gives a mixture of these two products which are otherwise difficult to separate, and it is also more convenient than most alternatives (CH 2 N 2 , or DCC/alcohol).…”

Section: Resultsmentioning

confidence: 99%

“…Since our method to prepare alkyl phosphinates results in enhanced thermal stability, [9] the prospect of extending the Schwabacher cross-coupling seemed excellent. The combination of the AHP cross-coupling [18] with our selective esterification of H-phosphinic acids [8] would provide the same overall transformation. However, this two-step approach presents some problems: First, the manipulation is complicated by the fact that the intermediate phosphinate salts must be acidified prior to the esterification to obtain good yields of esters; and second, the esterification step often requires long reaction times (12-24 h).…”

Section: Direct Formation Of H-phosphinate Estersmentioning

confidence: 99%

“…In some cases, the overall reaction may still proceed via the coupling of a salt followed by in situ esterification [22]. However, the HX which is produced during the coupling step must be essential to esterification, since the alkoxysilane esterification of pure H-phosphinate salts is very inefficient [8]. At least in the case of aryl iodides, the cross-coupling appears to proceed in a single step (like in the identical Schwabacher reaction [16a]) since some reactions conducted in the absence of a base (and therefore without the possibility for the formation of a hypophosphite salt) occur in nearly quantitative yields.…”

Section: Direct Formation Of H-phosphinate Estersmentioning

confidence: 99%

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Recent advances in phosphorus–carbon bond formation: synthesis of H-phosphinic acid derivatives from hypophosphorous compounds

Montchamp

2005

Journal of Organometallic Chemistry

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118

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“…In this reaction, the added aminopropyltriethoxysilane serves as a base in the Pd-catalysed reaction, and enables the esterification of the phosphinic acid in situ. [17][18][19] …”

Section: Figurementioning

confidence: 99%

Synthesis of meta and para-substituted aromatic sulfonate derivatives of polydentate phenylazaphosphinate ligands: enhancement of the water solubility of emissive europium(iii) EuroTracker® dyes

2014

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Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Results and DiscussionThe target complexes ( Fig. 1) include three strongly absorbing and equivalent chromophores, in which there is meta or para-sulfonic acid substituent in the phenyl ring of the phosphinate moiety. The sulfonation of this position was not expected to perturb the chromophore characteristics significantly, as the phosphorus oxygen bond and the aryl groups to which it is attached are not strongly conjugated, unlike a trigonal amide or carboxylate substituent.Previous X-ray analysis studies of these phenylphosphinate lanthanide complexes have revealed that the phenyl rings are oriented in the same direction, away from the plane of the 9-N 3 ring, and with the same relative configuration at phosphorus. 13,15,16 These structural studies also confirmed that the phosphorus-oxygen double bond lies out of the plane of the aryl rings. A simple retrosynthetic analysis suggests the intermediacy of a 2,4,6-trisubstituted pyridine, with a 4-Br group, allowing a Sonogashira coupling reaction to an arylalkyne in a final ligand assembly step. the P centres respectively, as deduced by X-ray and CD studies on related systems. [13][14][15][16] OBC 2014 Delbianco 3In order to form the C-P bond, a palladium-catalysed reaction was envisaged, allowing insertion of a 2-pyridyl group into the P-H bond of a phenylphosphinic ester, bearing a suitably protected sulfonate group. Following the studies of Miller, 6a the behaviour of the trifluoroethyl and phenylsulfonate esters as protecting groups for the sulfonic acid moiety was examined; each ester was derived from 3 or 4-bromo-phenylsulfonyl chloride (Scheme 1).Palladium-catalysed coupling between the aryl bromide and anilinium hypophosphite proceeded in 70% yield for the trifluoroethyl ester, but failed with the phenyl ester, probably due to competitive insertion into the O-Ph bond. In this reaction, the added aminopropyltriethoxysilane serves as a base in the Pd-catalysed reaction, and enables the esterification of the phosphinic acid in situ. 17-19 Scheme 1The di-esters 3 and 4 were used in coupling reactions with 2-bromo-4-nitro-6-methyl pyridine in degassed toluene using Cl 2 Pd[bis(diphenylphosphino)ferrocene] as the catalyst to give the phosphinate esters 5 and 6 (Scheme 2). Bromination with neat acetyl bromide followed by reesterification of the phosphinic acid group with HC(OEt) 3 allowed the isolation of intermediates 7 and 8 in 77 and 81 % yield respectively. Treatme...

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Orthosilicate-Mediated Esterification of Monosubstituted Phosphinic Acids

Cited by 55 publications

References 26 publications

Nickel-catalyzed C–P cross-coupling reactions of aryl iodides with H-phosphinates

Nickel-catalyzed C–P cross-coupling reactions of aryl iodides with H-phosphinates

Recent advances in phosphorus–carbon bond formation: synthesis of H-phosphinic acid derivatives from hypophosphorous compounds

Synthesis of meta and para-substituted aromatic sulfonate derivatives of polydentate phenylazaphosphinate ligands: enhancement of the water solubility of emissive europium(iii) EuroTracker® dyes

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