4‐Phosphorylated 1,2‐disubstituted imidazoles

Huryeva, A. N.; Marchenko, A. P.; Koidan, G. N.; Yurchenko, A. A.; Zarudnitskii, Evgenij V.; Пинчук, А. M.; Kostyuk, Alexander

doi:10.1002/hc.20584

Cited by 56 publications

(19 citation statements)

References 13 publications

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“…The 31 P NMR spectrum shows the signal for the acyclic compound 3a ( δ =14.4 ppm) and two resonance signals at δ = 9.8 and 10.2 ppm that are assigned to the cis and trans stereoisomers of 1,4‐dihydro‐1,4‐diphosphinines 4a , a′ (ratio 1:1.3), according to the relative positioning of the P –NMe 2 groups. The trans isomer of 4a is easily isolated from the isomeric mixture by washing the precipitate with THF, because of the higher solubility of the cis isomer, and hence, it can be unambiguously characterized, possessing a 31 P resonance at NMR spectrum at 9.4 ppm (CDCl 3 ); the value is slightly upfield‐shifted, compared with the reported derivatives IV (15.1–15.6 ppm).…”

Section: Resultsmentioning

confidence: 99%

“…Compounds IIIa , b (a: X = O; b: X = S) represent unique examples illustrating a synthetic approach to 1,4‐dihydro‐1,4‐diphosphinines relying on an elimination of chlorotrimethylsilane. Similarly, compound IV was obtained by the thermal reaction of the corresponding backbone, dichlorophosphanyl‐substituted 1‐methyl‐2‐alkyl‐imidazole, with pyridine (as the base), thus leading to the tricyclic heterocyclic scaffold shown in Figure . Hitherto, surprisingly few reactivity studies have been reported on mono‐, bi‐, or tricyclic 1,4‐dihydro‐1,4‐diphosphinines relying exclusively on derivatives possessing exocyclic P–C single bonds,, thus significantly restricting the opportunities of P functionalization.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Substitution, and Oxidation of Imidazole‐2‐thione Based Tricyclic 1,4‐Dihydro‐1,4‐diphosphinines

et al. 2018

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Herein, the synthesis and chemistry of P-functional tricyclic 1,4-dihydro-1,4-diphosphinines is described, following a recent communication on their use as precursors of 1,4-diphosphinines. In particular, ring formation of imidazole-2thione-based tricyclic 1,4-dihydro-1,4-diphosphinines 4a,b {-[P(Me 2 N)IMS R,R ] 2 -; IMS R,R = 1,3-dialkylimidazole-2-thione-4-yl}, first detected as side products, has been optimized to access 4d-f {-[P(Et 2 N)IMS R,R ] 2 -; IMS R,R = 1,3-dialkylimidazole-2-thione-4-yl}. The 1,4-dihydro-1,4-dichloro-1,4-diphosphinines 8a,b {-[P(Cl)IMS R,R ] 2 -; IMS R,R = 1,3-dialkylimidazole-2-thione-4-yl}, easily obtained from 4, are ideal starting materials for P-substituted products 9a-c (P-R; R = nBu, TMSC 2 -). The P-diorgano- [a] azole-2-derivatives, we recently described the first examples of tricyclic imidazole-2-thiones V having P-diethylamino groups ( Figure 1). [15] In the same short report, we also demonstrated a reductive conversion of P-Cl functional 1,4-dihydro-1,4-diphosphinines to give first examples of isolable 1,4-diphosphinines. [15] Following this short communication, we here report on detailed investigations on optimized synthetic protocols, as well as broad reactivity studies of P-functional tricyclic 1,4-dihydro-1,4-diphosphinines, to pave the way for their future use as unique ligands in coordination chemistry. Some reaction pathways and bonding situations have also been examined using DFT calculations. Results and DiscussionRecently, we demonstrated that backbone phosphanylation of imidazole-2-thiones allows access to acyclic dialkylaminobis(imidazole-2-thione-4-yl)phosphanes. [14] But in this study only imidazole-2-thiones with secondary or tertiary alkyl groups on either N-atoms (or at least on one) were used, and the final products were obtained in excellent yields without any byproducts. Interestingly, when 1,3-dimethyl imidazole-2-thione 1a, n-butyllithium, and dichloro(dimethylamino)phosphane 2a are used in THF, a white precipitate forms alongside the main product 3a (Scheme 1). The 31 P NMR spectrum shows the signal for the acyclic compound 3a (δ =14.4 ppm) and two resonance signals at δ = 9.8 and 10.2 ppm that are assigned to the cis and trans stereoisomers of 1,4-dihydro-1,4-diphosphinines 4a,a′ (ratio 1:1.3), according to the relative positioning of the P-NMe 2 groups. The trans isomer of 4a is easily isolated from the isomeric mixture by washing the precipitate with THF, because of the higher solubility of the cis isomer, and hence, it can be unambiguously characterized, possessing a 31 P resonance at NMR spectrum at 9.4 ppm (CDCl 3 ); the value is slightly upfieldshifted, compared with the reported derivatives IV (15.1-15.6 ppm [9] ).When the reaction is performed using 1,3-diethyl-imidazole-2-thione 1b, n-butyllithium and dichloro(dimethylamino)phosphane under the same conditions, a mixture of 3b and 4b is obtained (ratio 3:1), which is separable by column chromatography. The 31 P{ 1 H} NMR spectra of 3b and 4b (in CDCl 3 ) show similar chemical shifts as f...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, Substitution, and Oxidation of Imidazole‐2‐thione Based Tricyclic 1,4‐Dihydro‐1,4‐diphosphinines

et al. 2018

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“…The 1,4‐dihydro‐1,4‐diphosphinines, though well‐known since 1964, reactivity studies have received little attention. Recently, we reported on a new class of imidazole‐2‐thione‐based tricyclic 1,4‐dihydro‐1,4‐diphosphinines and their conversion into 1,4‐diphosphinines using dedichlorination under mild conditions .…”

Section: Introductionmentioning

confidence: 99%

The Quest for Twofold Reductive P–C Bond Cleavage of P–Ph Substituted 1,4‐Dihydro‐1,4‐diphosphinine Derivatives

et al. 2018

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It is demonstrated that backbone chloro(phenyl)phosphanyl-substituted imidazole-2-thiones 3 (N-R = Me, Et, nBu) can be easily synthesized which allow for a selective access to tricyclic 1,4-diphenyl-1,4-dihydro-1,4-diphosphinines 5 via reaction with LDA. Furthermore, new examples for preferred substitution reactions are provided that occurred when KHMDS was used thus yielding P-N(SiMe 3 ) 2 substituted derivatives 4.[a]

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“…Kostyuk and co-workers reported the synthesis of VI via reaction of the corresponding 1,4-dichloro-1,4-diphosphinine with dimethylamine. [9] Recently, we have reported the synthesis of VII using the aforementioned backbone-lithiation strategy of chlorophosphanyl-substituted imidazole-2-thiones. [10] Subsequently, reactivity studies of VII focused primarily on Pcentered BH 3 coordination chemistry or P-centered oxidation.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Oxidation Reactions of Thiazol‐2‐thione‐fused 1,4‐Dihydro‐1,4‐diphosphinines

2020

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Backbone (Et 2 N) 2 P-substituted thiazol-2-thione 2 [(Et 2 N) 2 P-THS Me ; THS Me = 3-methylthiazol-2-thione-5-yl] was employed in a stepwise reaction to access thiazol-2-thione-fused tricyclic 1,4-dihydro-1,4-diphosphinines 5 a,a' {-[P(Et 2 N)THS Me ] 2 ; optimization efforts led to excellent yields of 5 a,a' if LDA was used as the base. The same protocol could be exploited to access P-Ph derivatives 5 c,c'-d,d' {-[P(Ph)THS R ] 2 . Oxidation reactions of 5 a,a' using H 2 O 2 -urea, sulfur and grey selenium furnished the bis(P-oxides) 6,6', bis(P-sulfides) 7,7', and bis(P-selenides) 8,8', respectively. Reaction of 5 a,a' with o-chloranil led stereoselectively to bis(spirophosphorane) derivatives 9,9'.

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4‐Phosphorylated 1,2‐disubstituted imidazoles

Cited by 56 publications

References 13 publications

Synthesis, Substitution, and Oxidation of Imidazole‐2‐thione Based Tricyclic 1,4‐Dihydro‐1,4‐diphosphinines

Synthesis, Substitution, and Oxidation of Imidazole‐2‐thione Based Tricyclic 1,4‐Dihydro‐1,4‐diphosphinines

The Quest for Twofold Reductive P–C Bond Cleavage of P–Ph Substituted 1,4‐Dihydro‐1,4‐diphosphinine Derivatives

Synthesis and Oxidation Reactions of Thiazol‐2‐thione‐fused 1,4‐Dihydro‐1,4‐diphosphinines

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