Using density functional theory to calculate the anomeric effect in hydroxylamine and hydrazide derivatives of tetrahydropyran

Little is known about the magnitude of the anomeric effect in N-glycosylated oxyamines and hydrazides, limiting efforts toward the design of chemoselective acceptors that impose a stereochemical preference on glycosylation reactions. Thus, density functional theory (DFT) calculations were conducted to estimate the magnitude of the anomeric effect in N,O-dimethyl-N-(tetrahydro-2H-pyran-2-yl)hydroxylamine (1) and N'-(tetrahydro-2H-pyran-2-yl)acetohydrazide (3). The results show that N,O-dimethyl-N-(tetrahydro-2H-pyran-2-yl)hydroxylamine (1) displays a significant anomeric effect (AE_corr = 1.38 kcal/mol) and that N'-(tetrahydro-2H-pyran-2-yl)acetohydrazide (3) displays a modest anomeric effect (AE_corr = 0.54 kcal/mol).