Diels–Alder reactions of 5,6-dihydrothiazolo[3,2-d][1,4,2]diazaphospholes: A DFT investigation

Bansal, R. K.; Gupta, Neelima; Kumawat, Surendra K.

doi:10.1002/hc.20196

Cited by 8 publications

(2 citation statements)

References 66 publications

(30 reference statements)

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“…33 The observed stereo-and regioselectivities in the above reactions have been rationalized on the basis of the DFT calculations. 35,36 The reactions occur via pericyclic mechanism, the aromatic character of the transition structures, which are asynchronous, being confirmed by high negative nucleus-independent chemical shift (NICS) values. The calculated ratios of the endo/exo stereoisomers as well as those of the meta/para regioisomers agree nicely with the experimental results.…”

Section: Diels-alder Reactions Of Thiazolo[32-d][142]diazaphospholes and Their 56-dihydro And Benzo Derivativesmentioning

confidence: 95%

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Bansal

Kour

2015

Synlett

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The >C=P-functionality in annelated azaphospholes acts as a dienophile and undergoes Diels-Alder reactions with dienes. 1,3-Bis(alkoxycarbonyl)-2-phosphaindolizines react with dienes even in the absence of a catalyst; however, in the presence of an oxidizing agent such as sulfur or selenium, the reaction is much faster. 3-Alkoxycarbonyl-2-phosphaindolizines with an electron-withdrawing group exclusively at position 3 undergo the Diels-Alder reaction only in the presence of a Lewis acid. Density functional theory calculations reveal strong hyperconjugative interactions between the nitrogen lone pair and the >C=P-functionality of the 3-alkoxycarbonyl-2-phosphaindolizine, making it electron-rich. However, in 1,3-bis(alkoxycarbonyl)-2-phosphaindolizines, the ester group at the position 1 acts as a sink for the lone pair of electrons of nitrogen leaving the >C=P-functionality sufficiently electron-deficient to undergo the Diels-Alder reaction.

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Section: Diels-alder Reactions Of Thiazolo[32-d][142]diazaphospholes and Their 56-dihydro And Benzo Derivativesmentioning

confidence: 95%

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Bansal

Kour

2015

Synlett

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“…We have investigated the stereo-and regioselectivities observed in the above reactions theoretically at the DFT level (B3LYP/6-311++G**//B3LYP/6-311G**) [69,73]. The reactions occur via pericyclic mechanism, aromatic character of the transition structures which are asynchronous being confirmed by high negative NICS values.…”

Section: [2+4] Cycloadditionmentioning

confidence: 96%

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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Theoretical investigation of an unusual substituent effect on the dienophilicity of >CP functionality present in 2‐phosphaindolizines

Bansal

Gupta

Dixit

et al. 2008

J of Physical Organic Chem

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Effect of the number and positions of the methoxycarbonyl substituents in 2‐phosphaindolizine on the feasibility of its Diels–Alder (DA) reaction with 1,3‐butadiene has been investigated theoretically at the density functional theory (DFT) level. Among the series of four differently substituted 2‐phosphaindolizines, 3‐methoxycarbonyl‐2‐phosphaindolizine does not undergo the DA reaction due to the highest activation barrier (29.49 kcal mol−1) and endothermicity, whereas the activation barrier of the corresponding reaction of 1,3‐bis(methoxycarbonyl)‐2‐phosphaindolizine is lowest (22.43 kcal mol−1) with exothermicity making it possible to occur. This reactivity trend is corroborated by FMO energy gaps as well as by global electrophilicity powers of the reactants. Copyright © 2008 John Wiley & Sons, Ltd.

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Diels–Alder reactions of 5,6-dihydrothiazolo[3,2-d][1,4,2]diazaphospholes: A DFT investigation

Abstract: The density functional theory level (B3LYP/6-311G* * ) computations of the Diels-Alder (DA) reactions of 5,6-dihydrothiazolo[3,2-d]

Cited by 8 publications

References 66 publications

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Recent Advances in the Chemistry of Anellated Azaphospholes

Theoretical investigation of an unusual substituent effect on the dienophilicity of >CP functionality present in 2‐phosphaindolizines

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