Reversal of Stereoselectivity in Cycloadditions of Five-Membered Cyclic Nitrones Derived from Hexoses

Warning

This publication doesn't include Faculty of Arts. It includes Central European Institute of Technology. Official publication website can be found on muni.cz.
Authors

MALATINSKY T. SPISAKOVA M. BABJAK M. DOHANOSOVA J. MAREK Jaromír MONCOL J. FISCHER R.

Year of publication 2017
Type Article in Periodical
Magazine / Source European Journal of Organic Chemistry
MU Faculty or unit

Central European Institute of Technology

Citation
Web https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.201601488
Doi http://dx.doi.org/10.1002/ejoc.201601488
Keywords Heterocycles; Nitrones; Carbohydrates; Cycloaddition; Diastereoselectivity
Description Two five-membered cyclic nitrones derived from hexoses, a newly synthesized D-allo-configured nitrone and an already known D-talo-configured nitrone, have been examined in 1,3-dipolar cycloaddition reactions with vinyl acetate, allyl benzoate, methyl acrylate, acrylonitrile, and vinylene carbonate. The reactions of the D-allo-configured nitrone proceeded preferentially through the expected exo-anti transition state, but all the cycloadditions of the D-talo-configured nitrone surprisingly showed high exo-syn selectivity. This reversal of stereoselectivity has been explained by 3D analysis of the preferred conformations of the nitrones, obtained from X-ray data. The structures were further inspected using CONFLEX, PM5, and DFT calculations. All these methods revealed that the dioxolane substituents attached to C-5 of both nitrones had opposite spatial locations.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.