Conformational analysis of N-Boc-N,O-isopropylidene-α-serinals. A combined DFT and NMR study

This work describes an extensive conformational analysis of Garnerʹs aldehyde and its α-methylated homologue—two important chiral building blocks that are widely used in organic synthesis. A combination of density-functional theory and NMR spectroscopy confirmed the existence of a dynamic equilibrium between two possible conformers of the carbamate group in these compounds. The calculated properties such as conformer populations and rotational barriers around the (CO)–N bond are in good agreement with the experimental values. Finally, the dipole moments of the molecules appear to be a decisive factor in the stabilization of the conformers in solution.