Metaphosphate and metaphosphonic anhydride formation by thermolysis of 5,6-oxaphosphabicyclo[2.2.2]octenes; electrophilic .alpha.-substitution on a pyrrole

Quin, Louis D.; Marsi, B. G.

doi:10.1021/ja00297a079

Cited by 47 publications

(14 citation statements)

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“…The metaphosphate ion receives study as a possible intermediate in biological processes, a concept introduced in 1955 by the laboratories of F. H. Westheimer (6) and of C. A. Bunton (7). The 2,3-oxaphosphabicyclo[2.2.2]octene ring system, as embodied in derivatives of the basic structure 1, is a valuable source, on fragmentation, of several types of metaphosphoric acid derivatives (1)(2)(3)(4). A typical synthetic approach to such compounds is shown in Scheme 1.…”

Section: Present Scope Of the Heterocycle Fragmentation Methodsmentioning

confidence: 99%

“…We have demonstrated in several recent studies (1)(2)(3)(4) that certain unsaturated bicyclic frameworks containing phosphorus functions can be fragmented in solution to release a simple phosphorus-containing moiety. The nature of the bond breaking process leaves phosphorus in these fragments in a condition of low coordination (number of attached atoms) for the particular oxidation state concerned, and the method has proved of practical value for the synthesis of several low coordination species.…”

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confidence: 99%

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Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

Quin

Jankowski

Quin

et al. 1992

ACS Symposium Series

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The photochemical fragmentation of phosphine oxides with the 2-phosphabicyclo[2.2.2]octene framework constitutes a useful method for the generation of methylene(oxo)phosphoranes, R-P(O)=CH2. The previously uncharacterized and highly reactive P-phenyl and P -methyl derivatives were prepared and trapped with alcohols as phosphinates. The fragmentation also occurred when alkoxy substituents were present on phosphorus, but significant amounts of dialkyl phosphites were formed as by-products. Some new observations on the photochemical fragmentation of the 7-phosphanorbornene system have also been made. Contrary to literature reports, this system is resistant to fragmentation and does not extrude the 2-coordinate phosphoryl species. Fragmentation with loss of the phosphorus bridge does occur readily when an alcohol is also present in the medium. The data support a mechanism in which an initial photo-promoted addition reaction of the 7-phosphanorbornene and the alcohol occurs to form a 5-coordinate species, which undergoes the fragmentation. Thermal fragmentation of the 7-phosphanorbornenes is slow, but does appear to release the 2-coordinate phosphoryl species.We have demonstrated in several recent studies (1-4) that certain unsaturated bicyclic frameworks containing phosphorus functions can be fragmented in solution to release a simple phosphorus-containing moiety. The nature of the bond breaking process leaves phosphorus in these fragments in a condition of low coordination (number of attached atoms) for the particular oxidation state concerned, and the method has proved of practical value for the synthesis of several low coordination species. As a general rule, low-coordination phosphorus species are of very high reactivity and some types cannot be directly observed or isolated even when stabilization through kinetic or thermodynamic effects is attempted. In such cases, their intermediacy in chemical processes is usually demonstrated by trapping reactions. We continue to explore applications of the ring fragmentation approach in the low-coordination chemistry of phosphorus, and in this paper we will describe the first extension of our methods to the generation of two types of the 3-coordinate methylene(oxo)-

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Section: Present Scope Of the Heterocycle Fragmentation Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

Quin

Jankowski

Quin

et al. 1992

ACS Symposium Series

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“…For O-insertion a few equivalent excess of mchloroperbenzoic acid (mCPBA) was used as an oxygen atom donor (Scheme 2) [10,11]. After oxidation is complete the mixture of mCPBA and m-chlorobenzoic acid could be easily removed by complexation with anhydrous KF.…”

Section: Synthesis Of 23-oxaphosphabicyclo [222]octenes and 2-phosmentioning

confidence: 99%

“…Numerous types of substances have been phosphorylated, including alcohols [13], cholesterol [13], hydroquinone [27], amines [57], ethylene diamine [58], carbohydrates [59] and epoxides [11,60]. N-Methylpyrrole undergoes C-substitution [10] whereas thiophene was unreactive [2].…”

Section: Bicyclooctenes As Phosphorylating Agentsmentioning

confidence: 99%

2-Phospha- and 2,3-Oxaphosphabicyclo[2.2.2]octenes - Synthesis and Fragmentation to Low-coordinated Species

Jankowski¹,

Huben

2006

COC

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The 2-phosphabicyclo[2.2.2]octene and 2,3-oxaphosphabicyclo[2.2.2]octene systems undergo fragmentation in inert solvents on heating, or by UV-irradiation at room or low temperature. The fragmentation is of significance because it leads to the extrusion of low-coordinated species Y-P(X)O (Y = RO, R 2 N, Aryl; X = O, S, CH 2 ), which are very effective phosphorylating agents.This review covers different aspects of the 2-phosphabicyclo[2.2.2]octene and 2,3-oxaphosphabicyclo[2.2.2]octene derivatives. The first part is focused on their synthesis and structure. The reactivity of 2,3-oxaphosphabicyclooctenes involving rearrangement and fragmentation with release of the bridging P-O unit including mechanistic studies is described in the next part. The last part of the review is dedicated to the practical aspects of the utilization these compounds as phosphorylating agents.

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“…It is reasonable to assume that the highly electrophilic metaphosphate generated under the mild reaction conditions may be useful for other reactions in which metaphosphate esters have been shown to be useful previously. These include amines and electron rich aromatic rings such as anilines [36], pyrrols [37] and probably others.…”

Section: Fragmentation Of -Hydroxyiminobenzylphosphonate Polyhaloalkymentioning

confidence: 99%

Fragmentations and Rearrangements of α-Hydroxyiminoalkylphosphonates

Breuer¹

2006

COC

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Metaphosphate and metaphosphonic anhydride formation by thermolysis of 5,6-oxaphosphabicyclo[2.2.2]octenes; electrophilic .alpha.-substitution on a pyrrole

Cited by 47 publications

References 0 publications

Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

2-Phospha- and 2,3-Oxaphosphabicyclo[2.2.2]octenes - Synthesis and Fragmentation to Low-coordinated Species

Fragmentations and Rearrangements of α-Hydroxyiminoalkylphosphonates

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Metaphosphate and metaphosphonic anhydride formation by thermolysis of 5,6-oxaphosphabicyclo[2.2.2]octenes; electrophilic .alpha.-substitution on a pyrrole

Cited by 47 publications

References 0 publications

Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

Ring Fragmentation Approaches to Low-Coordinate Phosphorus Species

2-Phospha- and 2,3-Oxaphosphabicyclo[2.2.2]octenes - Synthesis and Fragmentation to Low-coordinated Species

Fragmentations and Rearrangements of &#945;-Hydroxyiminoalkylphosphonates

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Fragmentations and Rearrangements of α-Hydroxyiminoalkylphosphonates