Effects of Configuration and Substitution on C-H Bond Dissociation Enthalpies in Carbohydrate Derivatives: A Systematic Computational Study.

Density functional theory was used to calculate C-H bond dissociation enthalpies (BDEs) at each position of a diverse collection of pyranosides and furanosides differing in relative configuration and substitution patterns. A detailed analysis of the resulting data set (186 BDEs, calculated at the M06-2X/def2-TZVP level of theory) highlights the ways in which stereoelectronic effects, conformational properties, and noncovalent interactions can influence the strengths of C-H bonds in carbohydrates. The results point toward opportunities to alter the radical reactivity of carbohydrate derivatives by variation of their stereochemical configuration or the positions and types of protective groups.