Electronic and structural effects determining rotational barriers about the C-N bond in enamines of pyran-4-one and thiopyran-4-one - A theoretical MO ab initio approach to the interpretation of experimental results

摘要

Ab initio MO calculations were calTied out in 2-chloro-6-NR2-pyran-4-ones. 2-chloro-6-NR1-thipyran-4-ones and in thei protonated forms with the aim of discussing the electronic and structural effects mOOulating the rotational barriers about th C-N partial double bond measured in previous research. The balTiers in these molecules depend on NR2 substituents (pyrr