Conformational analysis of 3-methyltetrahydro-1,3-oxazine

Conformational analysis of 3-methyltetrahydro-1,3-oxazine has been performed using HF/6-31G(d), PBE/3z, and RI-MP2/lambda 2 simulation approximations. The potential energy surface contains eight minima. Interconversion of the axial and equatorial chair conformers (main minima) occurs via several independent pathways involving six twist forms. The preferred path presumes direct chair-chair transition via pyramidal inversion of the nitrogen atom.