36878-83-8Relevant academic research and scientific papers
SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES WITH NORBORNADIENE DERIVATIVES
Cristina, D.,Amici, M. De,Micheli, C. De,Gandolfi, R.
, p. 1349 - 1357 (2007/10/02)
The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbornadiene derivatives 1a-c showed varying degree of site- and stereo-selectivity.With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition.By contrast, 2-diazopropane and C-phenyl-N-methylnitrone react with the sole tetrasubstituted double bond of 1a-c in stereo- and site-specific cycloadditions.The quantitative evaluation of the two possible reaction paths was performed by glc analysis.The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1).The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.
