Synthesis, Crystal Structures, and Skeletal Inversion of Dithienodiphosphorines

Uchiyama, Yosuke; Kawaguchi, Toshifumi; Kuroda, Koichi

doi:10.1002/hc.21163

Cited by 8 publications

(9 citation statements)

References 33 publications

(10 reference statements)

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“…When compounds 3a – c were treated with LDA (1 equiv.) at –80 °C in THF, the 31 P{ 1 H} NMR spectra of the reaction mixtures showed two significantly high‐field shifted singlet resonance signals of the products (compared to 3a – c ) in different ratios that appeared very close to known 1,4‐diphenyl‐1,4‐dihydro‐1,4‐diphosphinines (Tableà); the selectivity of these reactions were quite remarkable as shown by the NMR spectra of the reaction mixture (Figure ). Multistep work‐up including flash chromatography provided access to 5a – c which were isolated as white powders in moderate to excellent yields (Table ).…”

Section: Resultsmentioning

confidence: 86%

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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Section: Resultsmentioning

confidence: 86%

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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“…The synthesis of I was achieved by Märkl by the reaction of diethynylphosphane with a primary phosphane, which led to new P‐substituted derivatives. The idea of replacing the benzannulated units in II by other rings led to other tricycles with tetrafluoro‐benzene, thiophene, xylene, and tetrathiafulvalene ring systems. 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.…”

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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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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“…The compound 2.1 contains an enamine fragment with exocyclic C-nucleophilic centre. Phosphorylation of compound 2.1 with phosphorous tribromide also proceeds with the participation of two nucleophilic C-centres, exactly, the endocyclic C3-thiophene atom and the exocyclic CH-centre, to form a new phosphoruscontaining fused system -1,2-dihydro-1λ 3…”

Section: Synthesis Of 12-dihydrothieno[23-b] [14]azaphosphinine Dementioning

confidence: 99%

“…Annelated phosphorus-containing heterocycles are widely studied as promising compounds for creating of new types of ligands for a metal-complex catalyst and complexons on their basis [1]. Five-, six-and sevenmembered P-containing heterocycles annelated with the thiophene nucleus were reported [2][3][4][5][6][7][8][9]. The main methods for their synthesis are based on interactions between lithium derivatives of thiophene and tri-or pentavalent phosphorus halides or esters [10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Annelated P- and N-containing Heterocycles Based on Methyl 5-Aminothiophene-2-Carboxylate Derivatives

Kovaleva¹,

Mayboroda²,

Simurova³

et al. 2019

ChChT

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Derivatives of new bicyclic systems-1H-thieno[3,2-c][1,5,2]oxazaphosphinine and 1,2-dihydrothieno[2,3-b][1,4]azaphosphinine have been obtained by phosphorylation of N-substituted derivatives of 5-amino-2-methoxycarbonylthiophene with phosphorus (III) tribromide. These heterocyclizations can be carried out in the basic medium and under mild conditions. The end reaction products were studied by means of chemical analysis, 1 H and 31 P NMR spectroscopy.

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Synthesis, Crystal Structures, and Skeletal Inversion of Dithienodiphosphorines

Cited by 8 publications

References 33 publications

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

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

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

Synthesis of Annelated P- and N-containing Heterocycles Based on Methyl 5-Aminothiophene-2-Carboxylate Derivatives

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