Ab initio and DFT search for conformational transition states of n-formyl-l-prolinamide

the w cis-trans isomers, backbone conformers (a-l, e-l y g-l) and syn-anty ring puckered structures of formyl l-prolinamide were studied at the rhf/3-21g, rhf/6-31g(d) and rb3lyp/6-31g(d) level of theory. in addition single point calculations using a more accurate and extended basis set (aug-cc-pvdz) were carried out. the barrier heights for cis-trans isomerization fell in the range of 19.58 to 24.6 kcal/mol and those for the interconversion between backbone conformations were in the range of 0.61-5.56 kcal/mol. the barrier heights for syn-anty ring puckering were found within 1.79 to 7.46 kcal/mol at the aug-cc-pvdz//rhf/3-21g level of theory.