Transition metal-free access to 3,4-dihydro-1,2-oxaphosphinine-2-oxides from phosphonochloridates and chalcones through tandem Michael addition and nucleophilic substitution

Fu, Zhiqiang; Sun, Simin; Yang, Anjian; Sun, Fang; Xu, Jiaxi

doi:10.1039/c9cc06352h

Cited by 13 publications

(17 citation statements)

References 29 publications

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“…Yield 78%; NMR spectra are in accordance with literature data [ 50 ]; white solid; m.p. 84.0–85.0 °C; 1 H NMR (400 MHz, DMSO-d 6 ) δ 7.62–7.33 (m, 2H), 7.33–7.05 (m, 2H), 4.46 (broad s, -OH and H 2 O), 3.88 (dq, J H-H = 7.0 Hz, J H-P = 6.6 Hz, 2H), 3.05 (d, J H-P = 21.3 Hz, 2H), 1.15 (t, J H-H = 7.0 Hz, 3H); 13 C NMR (101 MHz, DMSO-d 6 ) δ 133.0 (d, J C-P = 8.9 Hz), 131.9 (d, J C-P = 6.5 Hz), 130.9 (d, J C-P = 2.8 Hz), 119.3 (d, J C-P = 4.3 Hz), 60.5 (d, J C-P = 5.9 Hz), 33.0 (d, J C-P = 133.1 Hz), 16.3 (d, J C-P = 6.1 Hz); 31 P NMR (162 MHz, DMSO-d 6 ) δ 22.4.…”

Section: Methodssupporting

confidence: 80%

Selective Esterification of Phosphonic Acids

et al. 2021

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Here, we report straightforward and selective synthetic procedures for mono- and diesterification of phosphonic acids. A series of alkoxy group donors were studied and triethyl orthoacetate was found to be the best reagent as well as a solvent for the performed transformations. An important temperature effect on the reaction course was discovered. Depending on the reaction temperature, mono- or diethyl esters of phosphonic acid were obtained exclusively with decent yields. The substrate scope of the proposed methodology was verified on aromatic as well as aliphatic phosphonic acids. The designed method can be successfully applied for small- and large-scale experiments without significant loss of selectivity or reaction yield. Several devoted experiments were performed to give insight into the reaction mechanism. At 30 °C, monoesters are formed via an intermediate (1,1-diethoxyethyl ester of phosphonic acid). At higher temperatures, similar intermediate forms give diesters or stable and detectable pyrophosphonates which were also consumed to give diesters. 31P NMR spectroscopy was used to assign the structure of pyrophosphonate as well as to monitor the reaction course. No need for additional reagents and good accessibility and straightforward purification are the important aspects of the developed protocols.

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Section: Methodssupporting

confidence: 80%

Selective Esterification of Phosphonic Acids

et al. 2021

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“…However, the cycloaddition would give intermediate G , which would aromatize into cis , trans - 3a rather than product 3a (Scheme ). Arylmethylphosphonochloridate-generated arylphosphenes also underwent a stepwise annulation with α,β-unsaturated ketones rather than cycloaddition, supporting our assumed stepwise nucleophilic addition, intramolecular Friedel–Craft alkylation, and aromatization pathway.…”

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confidence: 99%

Annulation of Diaryl(aryl)phosphenes and Cyclic Imines to Access Benzo-δ-phospholactams

Luo

2020

Org. Lett.

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“…Phosphaheterocycles are a class of important organic compounds [1][2][3][4][5][6][7][8] and have been widely applied in agrochemicals, medicinal agents, and materials science [9,10]. They are also organic synthetic intermediates and building blocks [7,11,13].…”

Section: Introductionmentioning

confidence: 99%

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

Xu¹

2022

Beilstein J. Org. Chem.

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γ-Phostams include γ-phosphonolactams and γ-phosphinolactams and their fused derivatives, phosphorus analogues of γ-lactams. They are 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides and important biological five-membered azaphosphaheterocycles. They have been prepared through two major strategies of cyclizations and annulations. Cyclizations achieve ring construction through the formation of any bond in the ring, while annulations build the ring via [4 + 1] and [3 + 2] fashions with the simultaneous formation of two bonds. The review includes the synthesis of 1,2-azaphospholidine and 1,2-azaphospholine 2-oxides/sulfides and their fused derivatives.

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Transition metal-free access to 3,4-dihydro-1,2-oxaphosphinine-2-oxides from phosphonochloridates and chalcones through tandem Michael addition and nucleophilic substitution

Abstract: 3,4-Dihydro-1,2-oxaphosphinine 2-oxides are synthesized through tandem intermolecular nucleophilic addition and cyclization of phosphonochloridates and enones in the presence of base.

Cited by 13 publications

References 29 publications

Selective Esterification of Phosphonic Acids

Selective Esterification of Phosphonic Acids

Annulation of Diaryl(aryl)phosphenes and Cyclic Imines to Access Benzo-δ-phospholactams

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

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