Theoretical investigations on the mechanistic pathway of the thermal rearrangement of substituted N-acyl-2,2-dimethylaziridines

Abstract

The mechanism of the thermal rearrangement of substituted N-acyl-2,2-dimethylaziridines 1 has been studied using quantum chemistry methods. Geometries of reactants, transition states and products have been optimized at the B3LYP/6-311++G(2d,2p) level. Relative energies for various stationary points have been determined and reaction identified by IRC calculations. The results show that thermal rearrangements occur in three ways. Firstly, the transition state TS 1 in which a hydrogen atom of methyl groups migrates from primary carbon to oxygen of amid group to give the N-methallylamide 2. The second is via the transition state TS 2 in which the attack of oxygen to the tertiary carbon yields the oxazoline 3. The third is via the transition state TS 3 in which a hydrogen migrate from the secondary carbon to oxygen to give the vinylamide 4. In order to get insights into the factors determining the exact nature of its interactions with electrophiles, the application of reactivity parameters derived from density functional theory in a local sense, in particular the softness and Fukui function, to interpret and predict the mechanisms of the thermal decomposition of the N-acyl-2,2-dimethylaziridines 1, has been discussed.

A Short Route to the Ester (±) HomoSarkomycin via Johnson-Claisen Rearrangement

“…Where q k is the electronic population of atom k in a molecule. The corresponding local softness parameters can be defined as [ 29 - 31 ]:…”

Theoretical Density Functional Theory insights into the nature of chalcogen bonding between CX2 (X = S, Se, Te) and diazine from monomer to supramolecular complexes

“…[20] Geometries of the studied isolated monomers and formed complexes were optimized with the DFT method using the B3LYP-D3 [21][22][23] and B97-D3 functionals. [24][25][26] The Effective Core Potential (ECP) basis set LANL2DZ was used for chalcogen atoms (X = S, Se, Te) and 6-311 + G(d,p) was used for all other atoms (H, C, N).…”