The Stabilization of Glycosyl Cations Through Cooperative Noncovalent Interactions: A Theoretical Perspective

A systematic study of the stabilization of glycosyl cations on aromatic rings is reported at the B3LYP, M06-2X and M11 levels of theory. In particular, π-acidic arenes such as fluorobenzenes or naphthalenediimides efficiently stabilize these cations acting cooperatively as sandwich-type ternary cation-π-anion systems. The stabilization and cooperativity in polar (both protic and aprotic) and non-polar solvents has been also evaluated by using the polarizable continuum model. In addition, the role of the protecting group at the C-2 position (methyl, acetyl, benzyl, and pivaloyl) for this noncovalent stabilization has been explored, as well as the behaviour of the corresponding 2-deoxy glycosyl cation.