Ab initio study of the conrotatory ring opening of phospha- and azacyclobutenes. 2. Diphospha- and diazacyclobutenes

Bachrach, Steven M.; Liu, Meixiao

doi:10.1021/jo00033a026

Cited by 38 publications

(17 citation statements)

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“…The tert-butyl group on the phosphorus atom is trans to the Mes* group at the 4 position probably to minimize the steric congestion. Compound 3 seemed to be formed by cyclization of the intermediate including the 1,3-diphosphabuta-1,3-diene skeleton, which was predicted by theoretical calculation, 9,10 and might be formed from phosphaethenyllithium [Mes*C(Li) PR] and 1. No ring-opening reaction of the 1,3-diphosphacyclobutene skeleton giving the corresponding 1,3-diphosphabuta-1,3-diene was observed.…”

Section: Resultsmentioning

confidence: 83%

Synthesis and Characterization of Kinetically Stabilized 1,3-Diphosphacyclobutene Derivatives

Ito

Sugiyama

Yoshifuji

2004

Phosphorus, Sulfur, and Silicon and the Related Elements

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Section: Resultsmentioning

confidence: 83%

Synthesis and Characterization of Kinetically Stabilized 1,3-Diphosphacyclobutene Derivatives

Ito

Sugiyama

Yoshifuji

2004

Phosphorus, Sulfur, and Silicon and the Related Elements

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“…Using the sterically encumbered phosphaalkyne 2 , prepared by the 1,2‐elimination of disiloxane and the Fritsch‐Buttenberg‐Wiechell‐type rearrangement of phosphanylidenecarbene [Mes*P=C:],,,,, is useful to generate the phosphavinyl anion [RP=C(Li)Mes*] via the kinetically controlled regioselective nucleophilic addition of an organolithium reagent (RLi) ,. Prompt nucleophilic addition of the phosphavinyl anion [RP=C(Li)Mes*] to phosphaalkyne 2 affords 1,3‐diphosphacyclbuten‐4‐yl anion CBA via the [2+2] electrocyclization, of the anionic diphosphabutadiene intermediate (Scheme ) . Alkyllithiums, arylllithiums, silyllithiums, and lithium diisopropyl amide (LDA) are available to prepare the corresponding CBA .…”

Section: Chemistry Of 13‐diphosphacyclobuten‐4‐yl Anion (Cba)mentioning

confidence: 99%

Study of the Air‐Tolerant 1,3‐Diphosphacyclobutane‐2,4‐diyl through the Direct Arylation

Ito

2017

The Chemical Record

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Installing π-functional substituents on the skeletal phosphorus atoms of the air-tolerant 1,3-diphosphacyclobutane-2,4-diyl unit are promising for tuning the open-shell singlet P-heterocyclic chromophore. The sterically encumbered 1,3-diphosphaCycloButen-4-yl Anion (CBA), generated from the phosphorus-carbon triple bond, was available for the regioselective arylation via nucleophilic aromatic substitution (S Ar) reaction, addition to arynes, and single-electron transfer (SET) process affording the corresponding P-arylated 1,3-diphosphacyclobutane-2,4-diyls. The photo-absorption and redox properties correlated with the effects of the aryl substituents on the 1,3-diphosphacyclobutane-2,4-diyl unit. The X-ray analyses enabled not only to discuss the metric parameters but also to visualize the radicalic electrons via the electron-density distribution analysis. The electron-donating character of the P-heterocyclic chromophores induced the p-type semiconductor behavior. Detection of hydrogen fluoride via formation of the 1λ ,3λ -diphosphete derivative was also developed.

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“…The mechanism of the cycloaddition of ketene and imine is found to H I I H be a two-step process with a zwitterionic intermediate. 49 The electrocyclic conrotatory closure of this intermediate is predicted to be the rate determining step. The conrotatory ring opening in phospha-and azacyclobutenes is found to be thermoneutral, or very slightly endothermic, for dihydrophosphates but exothermic for dihyd-r~azetes.~' The energies of activation for the opening of 2,3-dihydrophosphete and ization permits the prediction of other transition state geometries and energies.…”

Section: A B Initio Calculations Of Tautomerism Between Formhydroxami...mentioning

confidence: 99%

Chapter 3. Theoretical organic chemistry

McDouall¹

1992

Annu. Rep. Prog. Chem., Sect. B

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The high level of activity in the area of density functional theory continues and a number of useful assessments of various aspects have appeared. Notable amongst these is a detailed review of the methodology of the DGauss program' and its application to many organic systems. Fan and Ziegler2 also provide an assessment of their density functional formalism, through its application to the calculation of activation energies for elementary organic reactions, the results of which are very encouraging. Application of density functional theory to the calculation of 27 homolytic dissociation reactions using generalized valence bond (GVB) reference wavefunctions3 and a modest basis set (&3 lG(D)), show an average error of 4 kcal: mol-'. The use of the same basis set and Hartree-Fock reference wavefunctions with a density function treatment of exchange and correlation4 for a set of 106 experimentally well established atomization energies, ionization potentials, and proton affinities show a mean absolute deviation of only 4.18 kcal mol-'. Other tests of density functional using the large G1 database of Pople and co-workers' have also shown these approaches to provide accurate and computationally efficient methods for studying chemical reactions.Though not directly related to density functional theory, an interesting analysis of the effect of electron correlation on charge density distributions in molecules has been carried out for the widely used MP2, CISD, and QCISD wavefunctions.8 Compared to the QCI density, MP2 is found to consistently exaggerate the loss in charge density in bonding regions leading to an increase in bond length, whereas CISD is found to underestimate the shift.Pople and co-workers have provided a detailed overview of their approach to the molecular orbital theory ofexcited states.' The method is now applicable to quite large

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Ab initio study of the conrotatory ring opening of phospha- and azacyclobutenes. 2. Diphospha- and diazacyclobutenes

Cited by 38 publications

References 1 publication

Synthesis and Characterization of Kinetically Stabilized 1,3-Diphosphacyclobutene Derivatives

Synthesis and Characterization of Kinetically Stabilized 1,3-Diphosphacyclobutene Derivatives

Study of the Air‐Tolerant 1,3‐Diphosphacyclobutane‐2,4‐diyl through the Direct Arylation

Chapter 3. Theoretical organic chemistry

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