Plausible transition states for glycosylation reactions

► First attempt at including donor, acceptor, promoter, and solvent in glycoside formation modeling. ► Long range (2.725 Ǻ) interactions of acceptor oxygens with donor C-1 during ionization identified. ► Promoter in TS and is the most strongly solvated molecule. ► SSIP-like Transition States identified for α- or β- attack on β- or α-triflates. ► Orientation of the nucleophile identified as key determinant of stereospecificity.