ChemInform Abstract: REACTIONS OF ESTERS OF N‐PHENYL‐N‐(TRIMETHYLSILYL)AMIDO PHOSPHORUS(V) ACIDS WITH ELECTROPHILIC REAGENTS

Nesterov, L. V.; Krepysheva, N. E.; Sabirova, R. A.

doi:10.1002/chin.197602239

Cited by 2 publications

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“…Dialkyl 1-(trimethylsilyloxy) alkylphosphonates are generally synthesized in good yield by the reaction of silylphosphites with carbonyl compounds [5][6][7] . Numerous examples of this reaction have been reported,Much of the original work was done by Russian chemists.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and Reaction of Dialkyl 1-(Trimethylsilyloxy)aikylphosphonates

Li¹,

Zhu²

1995

Main Group Metal Chemistry

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Section: Discussionmentioning

confidence: 99%

Synthesis and Reaction of Dialkyl 1-(Trimethylsilyloxy)aikylphosphonates

Li¹,

Zhu²

1995

Main Group Metal Chemistry

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“…The reactions of aldehydes and ketones with acyl phosphites is reported for the preparation of aacetyloxyphosphonates at 120 °C to produce the desired products in low yields. 3 The other reported procedures for this purpose include direct acetylation of ahydroxyphosphonates 4 with ketene catalyzed by BF 3 •OEt 2 5 or H 2 SO 4 . 6 These protocols suffer from usually low yields 5 , requiring rather high temperatures (70-80 °C) and long reaction times (10-15 h).…”

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confidence: 99%

Facile and High-Yielding Preparation of α-Acetoxyphosphonates from α-Hydroxyphosphonates Assisted by Microwave Irradiation

Firouzabadi¹,

Iranpoor²,

Sobhani³

et al. 2004

Synthesis

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A convenient and eco-friendly procedure is described for the efficient preparation of a variety of a-acetyloxyphosphonates from their corresponding a-hydroxyphosphonates using acetic anhydride under microwave irradiation in the absence of solvent.a-Acetyloxyphosphonates are considered as important and valuable phosphorus compounds for the synthesis of optically active a-hydroxyphosphonates. Enzymatic systems have been introduced for the enantioselective hydrolysis of racemic a-acetyloxyphosphonates. 1 Chiral and nonracemic a-hydroxyphosphonates are useful precursors for a variety of a-substituted phosphonates, especially for a-aminophosphonic acids which in recent years have received considerable attention owing to their potential activities as analogues of a-amino acids 1a,2 in medical, bioorganic and organic chemistry.A literature survey reveals that practical and high yielding methods for the synthesis of pure a-acetyloxyphosphonates are rare. The reactions of aldehydes and ketones with acyl phosphites is reported for the preparation of aacetyloxyphosphonates at 120 °C to produce the desired products in low yields. 3 The other reported procedures for this purpose include direct acetylation of ahydroxyphosphonates 4 with ketene catalyzed by BF 3 ·OEt 2 5 or H 2 SO 4 . 6 These protocols suffer from usually low yields 5 , requiring rather high temperatures (70-80 °C) and long reaction times (10-15 h). 6 Acetylation of a-hydroxyphosphonates with Ac 2 O or AcCl in the presence of Et 3 N or pyridine was conducted at room temperature in 1-18 hours, providing products in yields ranging from low to excellent. 1b,c,7 In another reported procedure, AcCl was used for direct acetylation of a-trimethylsilyloxyphosphonates at a rather high temperature (120 °C) to produce aacetyloxyphosphonates in moderate yields (55-70%). 8Recently, the application of microwave irradiation has gained popularity in organic synthesis 9 particularly in chemical reactions, which are carried out under solventfree conditions. Combination of solvent-free conditions and microwave irradiation leads to noticeable reductions in reaction times, enhancement of the efficiency of the reactions, sometimes their selectivity plus several other advantages could be considered as an eco-friendly approach that is termed green chemistry. 9b,10We have recently paid attention to the chemistry of diethyl a-hydroxyphosphonates and introduced new methods for their direct transformation to other derivatives. 11 In this article, we present a new solventless procedure in which microwave irradiation is employed for the direct acetylation of various types of a-hydroxyphosphonates 1a-o to provide the corresponding a-acetyloxyphosphonates 2a-o in excellent yields with Ac 2 O as an acetylating agent (Scheme 1 and Table 1). Scheme 1As shown in Table 1, various types of diethyl a-hydroxy(phenylmethyl)phosphonates 1a-k were cleanly converted into their corresponding diethyl a-acetyloxyphosphonates 2a-k in excellent yields (90-98%). Diethyl a-hydroxy-2-naphthyl-, 3-pyridyl-, alk...

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ChemInform Abstract: REACTIONS OF ESTERS OF N‐PHENYL‐N‐(TRIMETHYLSILYL)AMIDO PHOSPHORUS(V) ACIDS WITH ELECTROPHILIC REAGENTS

Abstract: N‐Phenyl‐N‐trimethylsilylamido‐O‐dialkylphosphate (Ia) bzw. ‐O‐alkyl‐methylphosphonate (Ib) bilden mit Chloral (II) die Trimethylsilylester (III) und N‐Trichloräthyliden‐anilin (IV).

Cited by 2 publications

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Synthesis and Reaction of Dialkyl 1-(Trimethylsilyloxy)aikylphosphonates

Synthesis and Reaction of Dialkyl 1-(Trimethylsilyloxy)aikylphosphonates

Facile and High-Yielding Preparation of α-Acetoxyphosphonates from α-Hydroxyphosphonates Assisted by Microwave Irradiation

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