Alkylation of Tetra-<i>n</i>-butylaminium Alkyl Hydrogen Phosphites. A New Route to Mixed Dialkyl Phosphites

Kluba, M.; Zwierzak, A.

doi:10.1055/s-1978-24687

Cited by 15 publications

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“…Given the modest, albeit positive, results obtained using diphenyl phosphite, we explored other H -phosphonate-based reagents ( 5 – 7 , Scheme ) to affect this transformation. The preparation of 5 – 7 involved first the conversion of methyl H –phosphonate ammonium salt 3 into its tetra- N -butylammonium counterpart ( 4 ) . Reagent 5 can be synthesized by the addition of pivaloyl chloride (PivCl) to 4 in pyridine .…”

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Synthesis of Carbohydrate Methyl Phosphoramidates

Ashmus

Lowary

2014

Org. Lett.

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A two-step route for introducing methyl phosphoramidate moieties onto carbohydrates is reported. The approach uses methyl pivolyl H-phosphonate as the phosphorylating reagent to produce an isolable carbohydrate H-phosphonate intermediate that is then oxidized by a Todd-Atherton reaction. The stability of the product methyl phosphoramidates was subsequently evaluated using various deprotection strategies.

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confidence: 99%

Synthesis of Carbohydrate Methyl Phosphoramidates

Ashmus

Lowary

2014

Org. Lett.

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“…Moreover, approach a-2 requires the use of explosive and toxic tetrazole 7 to activate E and F. In comparison, approach b is initiated by preparing phosphite G by adding excess R 1 OH relative to B. The subsequent hydrolysis of G affords symmetrical Hphosphonate H. Either transesterification 8 of H with R 2 OH (b-1) or hydrolysis of H and subsequent alkylation 9 of D (b-2) affords the desired A. Both approaches also require temporal substitution of the chlorine atoms in B with an OR 1 group (b-1) or OR 1 and OH groups (b-2) to suppress the overreaction, along with purification of the intermediate.…”

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confidence: 99%

“…The subsequent hydrolysis of G affords symmetrical H -phosphonate H . Either transesterification of H with R 2 OH (b-1) or hydrolysis of H and subsequent alkylation of D (b-2) affords the desired A . Both approaches also require temporal substitution of the chlorine atoms in B with an OR 1 group (b-1) or OR 1 and OH groups (b-2) to suppress the overreaction, along with purification of the intermediate.…”

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confidence: 99%

Microflow Synthesis of Unsymmetrical H-Phosphonates via Sequential and Direct Substitution of Chlorine Atoms in Phosphorus Trichloride with Alkoxy Groups

Tanaka,

Kitamura,

Fuse

2024

J. Org. Chem.

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Unsymmetrical H-phosphonates were synthesized by a rapid (<15 s) and mild (20 °C) process in a microflow reactor as the first example of the sequential direct substitution of the chlorine atoms in PCl 3 with alkoxyl/aryloxy groups using equivalent amounts of PCl 3 and alcohols. The optimal base concentration differed in each step, presumably attributed to differences in the Brønsted basicity of the electrophilic intermediates. Phosphite hydrolysis was observed, and the structure−hydrolysis relationship was quantitatively evaluated.

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Selektive Katalyse mit Übergangszustands‐Analoga‐geprägtem Siliciumdioxid

Heilmann

Maier

1994

Angewandte Chemie

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Eine auf -78 'C gekfihlte Losung von 0.267 g (0.755 mmol) epi-1 a in 3 mL wasserfreiem THF wurde unter Schutzgas rnit 1.1 Aquiv. nBuLi (1.6 M in Hexan) und nach 15 min mit 1.2 Aquiv. CITi(OiPr), (1.0 mmolg-' in Hexan) verselzt. Nach 5 min erwarmt man auf 0°C. ruhrt 55 min nach, kiihlt anschlieknd wieder auf -78°C und tropft 2.0 Aquiv. 2-Methylpropanal LU. 15 min danach wird die Reaktionslosung unter kraftigem Ruhren auf geszttigte wiBrige (NH,),CO,-Losung (20 mL) gegossen, nach weiteren 30 min mit Ether extrahiert und die organische Phase uber MgSO, getrocknet. Man lost das Rohprodukt in 4 mL THF, tropft 1.2 Aquiv. nBu,NF(I.I M~~T H F ) beiO"C7u.gieRt nach 15 minauf20mLEisundextrdhiert mit Ethylacetat. Nach Trocknung der organischen Phase uber MgSO, und Flash-Chromatographie an Kieselgel (Eluent: Ethylacetat/Hexan) erhilt man 0.229 g (0.648 mmol, 86%) 7b als farbloses 01.

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Alkylation of Tetra-n-butylaminium Alkyl Hydrogen Phosphites. A New Route to Mixed Dialkyl Phosphites

Cited by 15 publications

References 0 publications

Synthesis of Carbohydrate Methyl Phosphoramidates

Synthesis of Carbohydrate Methyl Phosphoramidates

Microflow Synthesis of Unsymmetrical H-Phosphonates via Sequential and Direct Substitution of Chlorine Atoms in Phosphorus Trichloride with Alkoxy Groups

Selektive Katalyse mit Übergangszustands‐Analoga‐geprägtem Siliciumdioxid

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