54527-51-4Relevant academic research and scientific papers
α-Acyloxynitroso dienophiles in [4+2] hetero Diels-Alder cycloadditions: mechanistic insights
Calvet, Géraldine,Coote, Susannah C.,Blanchard, Nicolas,Kouklovsky, Cyrille
supporting information; experimental part, p. 2969 - 2980 (2010/06/20)
α-Acyloxynitroso derivatives are a class of heterodienophiles leading to valuable 3,6-dihydro-1,2-oxazines or the corresponding aminoalcohols in good yields. The discovery that a β-oxygenated moiety led to a domino [4+2] cycloaddition/σN-O bond cleavage in the presence of a catalytic amount of Lewis acid was investigated in detail, through kinetic profiling of the reaction both in the absence and presence of a promoter. These studies showed that the role of the Lewis acid was to accelerate the σN-O bond cleavage thereby promoting a highly reproducible sequence. In addition, our preliminary results on an asymmetric version of this domino sequence are reported.
Solution structure of some λ3 iodanes: An 17O NMR and DFT study
Mocci, Francesca,Uccheddu, Gianluca,Frangia, Angelo,Cerioni, Giovanni
, p. 4163 - 4168 (2008/02/05)
(Figure Presented) The structure of a series of I-O bonded bis(acyloxy)iodoarenes and benzoiodoxolones in chloroform solution has been investigated by 17O NMR spectroscopy and by density functional theory (DFT) calculations, employing the PBE0 functional together with the LANL2DZ basis set extended with polarization (d) and diffuse (p) functions. This combined approach allowed us to ascertain that, although these classes of λ3 iodanes maintain in chloroform solution their solid state "T-shaped" structure, a degenerate [1,3] sigmatropic shift of iodine between the two oxygens of the acyloxy groups occurs in solution. The energy barrier involved in this process differs in the two classes, thus causing significant differences in the 17O NMR spectra, at room temperature, of the two classes of compounds.
