Three or Four Heteroatoms including at least One Phosphorus

Schmidpeter, Alfred

doi:10.1016/b978-008096518-5.00100-3

Cited by 11 publications

(13 citation statements)

References 215 publications

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“…The reaction of 1 with 2,3-dimethylbutadiene alone was found to be sluggish at room temperature and could be completed (δ 31 P = 14.1) only on refluxing in chloroform for 4 days [38]. The role of sulfur or methyl iodide therefore appears to push a reversible reaction between the 1,3-azaphosphole ring and diene in the forward direction by oxidizing 3 Similarly, complete regioselectivity has been reported in the reaction of 2-acetyl-1,2,3-diazaphosphole with isoprene [33]. The reaction of 2-acetyl-1,2,3-diazaphosphole with cyclopentadiene gave an endo-product immediately (15 min, 15…”

Section: [2 + 4] Cycloadditionsmentioning

confidence: 99%

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Cycloaddition reactions of heterophospholes

Bansal

Gupta

2004

Heteroatom Chemistry

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Section: [2 + 4] Cycloadditionsmentioning

confidence: 99%

“…Heterophospholes are five-membered 6 aromatic systems having a two-coordinate, tervalent ( 2 , 3 ) phosphorus which contributes one electron to the aromatic sextet [1][2][3][4]. In the neutral heterophosphole ring, besides sp 2 -phosphorus, there must be at least one heteroatom like NR, O, or S(Se,Te) contributing two -electrons.…”

Section: Introductionmentioning

confidence: 99%

Cycloaddition reactions of heterophospholes

Bansal

Gupta

2004

Heteroatom Chemistry

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“…Azaphospholes belong to the general class of heterophospholes, which are five-membered 6 aromatic systems having at least one two-coordinate tervalent ( 2 , 3 ) phosphorus atom that contributes only one electron to the aromatic sextet [1][2][3][4][5]. The aromatic sextet in the neutral heterophosphole ring is completed by the contribution of two -electrons by another heteroatom like NR, O, S (Se, Te) or even a 3 , 3 -phosphorus atom.…”

Section: Introductionmentioning

confidence: 99%

“…Two reviews deal with the synthesis of anellated heterophospholes from 2-unsubstituted cycloiminium salts [13,14]. The reviews on heterophospholes in general include anellated azaphospholes, though in a limited manner [1][2][3][4][5]. The reviews dealing primarily with the synthetic uses of phosphaalkynes also include the synthesis of anellated azaphospholes through [3+2] cycloaddition [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in the Chemistry of Anellated Azaphospholes

Bansal¹,

Gupta²,

Kumawat

2007

COC

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Azaphospholes are 6 aromatic heterocycles incorporating at least one 2 , 3 -phosphorus atom and one 3 , 3nitrogen atom. This review covers the synthesis, structural characterization, reactions and theoretical calculations of azaphospholes anellated to a six-or five-membered heterocyclic ring, reported during the last 10-12 years. Three synthetic methods, namely [4+1] cyclocondensation, [3+2] cyclocondensation and 1,5-electrocyclization make a variety of these phosphorus heterocycles available. The aromatic character of these compounds has been confirmed by carrying out density functional theory (DFT) calculations. Mainly 1 H, 13 C and 31 P NMR studies have been employed for the structural characterization. Almost all the functionalities present in the azaphosphole ring have been investigated and electrophilic substitution reactions of the 1-unsubstituted compounds and Diels-Alder reactions as well as 1,2-addition reactions to the >C=P-moiety have been accomplished successfully. The stereo-and regioselectivities observed in the Diels-Alder reactions have been explained on the basis of DFT calculations. Cheletropic cycloadducts formed from [4+1] cycloaddition of o-quinones on the 2 , 3 -P atom have been obtained. A variety of coordination compounds formed bycoordination of the 2 , 3 -P atom have been prepared.

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“…In azaphospholes, the two-coordinate phosphorus represents the main center of reactivity. A large number of 1,2-addition reactions of various reagents across the P‫ס‬C or P‫ס‬N double bond have been reported for electron-poor azaphospholes [1,[10][11][12]. These additions may or may not be accompanied by an oxidation of the phosphorus atom.…”

Section: Introductionmentioning

confidence: 99%