Bond-shift isomers: the co-existence of allenic and propargylic phenylnitrile imines.

@article{Nunes2015BondshiftIT,
  title={Bond-shift isomers: the co-existence of allenic and propargylic phenylnitrile imines.},
  author={Cl{\'a}udio M. Nunes and Igor Reva and Rui Fausto and Didier B{\'e}gu{\'e} and Curt Wentrup},
  journal={Chemical communications},
  year={2015},
  volume={51 79},
  pages={
          14712-5
        }
}
We discovered a 1,3-dipolar species co-existing in two different structures. Photolysis of matrix-isolated 5-phenyltetrazole generates two forms of phenylnitrile imine: propargylic and allenic. They are not resonance structures but correspond to different energy minima, representing bond-shift isomers. These distinct species were characterized spectroscopically and confirmed by calculations up to the CASSCF(14,12) theory level. 
24 Citations
Reverse orientation in the ultrasound-assisted [3 + 2]-cycloaddition reaction of nitrile imines with 3-formylchromone-Meldrum's acid adducts.
The [3 + 2]-cycloaddition reaction of nitrile imines with 2,2-dimethyl-5-[(4-oxo-4H-chromen-3-yl)methylene]-1,3-dioxane-4,6-dione tends to form the reverse-orientation products under ultrasoundExpand
Nitrile Imines and Their Properties
This chapter introduces the nitrile imine 1,3-dipole, examining the history behind its discovery and the core spectroscopic characteristics associated with the species. The different resonance formsExpand
Singlet Photoreactivity of 3-Methyl-2-phenyl-2H-azirine
Irradiation of 3-methyl-2-phenyl-2H-azirine (1) at 254 nm in argon matrices results in ylide 6. Similarly, laser flash photolysis (λ = 266 nm) of azirine 1 in acetonitrile yields ylide 6, which has aExpand
Photochemistry of 3-amino-1,2-benzisoxazole: unexpected photoisomerization of an amino-spiro-2H-azirine to a 1H-diazirine
Abstract UV irradiation of 3-amino-1,2-benzisoxazole isolated in an argon matrix leads to the formation of an amino-spiro-2 H -azirine. The amino-spiro-2 H -azirine was found to photoisomerize backExpand
Rearrangements of Nitrile Imines: Ring Expansion of Benzonitrile Imines to Cycloheptatetraenes and Ring Closure to 3-Phenyl-3 H-diazirines.
TLDR
A competing rearrangement of benzonitrile imine forms 3-phenyl-3 H-diazirine, which is a precursor of phenyldiazomethane and hence phenylcarbene, and this reaction is competitive with the ring expansion. Expand
Photochemistry of 2-Formylphenylnitrene: A Doorway to Heavy-Atom Tunneling of a Benzazirine to a Cyclic Ketenimine.
TLDR
The heavy-atom tunneling reaction involving spontaneous ring expansion of a fused-ring benzazirine into a seven-membered ring cyclic ketenimine is discovered and it was found that the ring-expansion reaction rate is more than 1 order of magnitude faster when the sample is exposed to broadband IR radiation. Expand
Photochemistry of 1- and 2-Methyl-5-aminotetrazoles: Structural Effects on Reaction Pathways.
TLDR
The structural and vibrational characterization of both reactants and photoproducts has been undertaken and observation of the amino cyanamide 4 represents a novel reaction pathway in the photochemistry of tetrazoles and seems to be characteristic of 1H-tetrazoles. Expand
Conformational Analysis, Spectroscopy and Photochemistry of Matrix-Isolated 1H- and 2H- Tautomeric Forms of Ethyl Tetrazole-5- Carboxylate
Abstract The preferred conformations, infrared spectra and photochemistry of matrix-isolated 1H- and 2H- tautomers of ethyl tetrazole-5-carboxylate (ET5C) were investigated. Experimentally, isolatedExpand
On the Photochemistry of 1,2‐Benzisoxazole: Capture of Elusive Spiro‐2H‐azirine and Ketenimine Intermediates
The photochemistry of 1,2-benzisoxazole (1) was studied using low-temperature matrix isolation coupled with infrared spectroscopy and quantum chemistry calculations. We identified, for the firstExpand
-Rearrangements of Aromatic Nitrile Oxides and Nitrile Ylides. Potential Ring Expansion to Cycloheptatetraene Derivatives Mimicking Arylcarbenes.
TLDR
Calculations at DFT and CASPT2 levels of theory reveal novel, potential rearrangements, in which the aromatic 1,3-dipoles mimic phenylcarbene and undergo ring expansion to cycloheptatetraene derivatives. Expand
...
1
2
3
...

References

SHOWING 1-10 OF 51 REFERENCES
Kinetics and Mechanism of 1,3‐Dipolar Cycloadditions
Criteria for the mechanism of 1,3-dipolar cycloadditions which lead to 5-membered rings are provided by the stereoselectivity observed with cis-trans isomeric dipolarophiles, by the effect of solventExpand
Generation and characterization of a 4π-electron three-membered ring 1H-diazirine: An elusive intermediate in nitrile imine-carbodiimide isomerization.
TLDR
For the first time, a 1H-diazirine was captured as intermediate in the photoisomerization of nitrile imines into carbodiimides. Expand
Asymmetric catalytic 1,3-dipolar cycloaddition reaction of nitrile imines for the synthesis of chiral spiro-pyrazoline-oxindoles.
A new 1,3-dipolar cycloaddition of nitrile imines with 3-alkenyl-oxindoles was catalyzed by a new chiral Mg(ClO(4))(2) complex of an N,N'-dioxide ligand. The reaction is so far the sole catalyticExpand
1,3-Dipolar Cycloadditions. Past and Future†
In contrast to the very large number of special methods applicable to syntheses in the heterocyclic series, relatively few general methods are available. The 1,3-dipolar addition offers a remarkablyExpand
Di(9-anthryl)carbene Revisited. Product Analysis and Spectroscopic Studies
Irradiation (λ > 300 nm) of di(9-anthryl)diazomethane (1) in degassed benzene gave the trimer (3) of dianthrylcarbene (2) as the main product along with a small amount of a tetramer (4). The struct...
Structure of Nitrilimine - Allenic or Propargylic
High-level ab initio molecular orbital calculations, using basis sets up to 6-311+G(2df,2p), with electron correlation incorporated at the quadratic configuration interaction (QCISD) level, have beenExpand
Fast alkene functionalization in vivo by Photoclick chemistry: HOMO lifting of nitrile imine dipoles.
TLDR
Extremely fast fluorescence labeling of a recombinant alkene-encoded protein in living Escherichia coli cells was observed with tetrazole 1.0, which greatly accelerates the functionalization of alkenes by 1,3-dipolar cycloaddition in living systems. Expand
The electronic structure of nitrilimines revisited.
A combination of density-functional theory and natural resonance theory has been used to show that a complete description of the electronic structure of nitrilimines, R(1)CNNR(2), requires fourExpand
Nitrile Imines: From Matrix Characterization to Stable Compounds
The concept of 1,3-dipolar cycloaddition was developed, starting in the late 1950s, largely by Rolf Huisgen and his students in Munich, and it has led to one of the most versatile methods for theExpand
Infrared-spectroscopic study of amino-substituted nitrilimines and their photochemical transformations in an argon matrix
3-Amino- and 3-(dimethyl)amino-1-methylnitrilimines were obtained by the photolysis (l = 254 nm) of the corresponding 5-amino- and 5-(dimethyl)amino-2-methyltetrazoles in an argon matrix at 10 K orExpand
...
1
2
3
4
5
...