An MEDT study of the carbenoid type [3 2] cycloaddition reactions of nitrile ylides with electron deficient chiral oxazolidinones.
The molecular mechanism of the carbenoid type [3 2] cycloaddition (32CA) reactions of a nitrile ylide (NY) with a non chiral and a chiral oxazolidinone has been studied within Molecular Electron Density Theory (MEDT) at the MPWB1K/6 31G(d) computational level. Topological analysis of the Electron Localisation Function (ELF) of the NY shows that it presents a carbenoid structure. The high nucleophilic character of the NY together with the electrophilic character of the non chiral oxazolidinone favour a polar 32CA reaction with a very low activation energy, the reaction being completely meta/endo selective. A Bonding Evolution Theory (BET) study of the molecular mechanism makes it possible to characterise a two stage one step carbenoid type mechanism. Non Covalent Interactions (NCI) analysis of the 32CA reaction between the NY and chiral oxazolidinone correctly explains the diastereoselectivity experimentally observed.
Organic biomolecular chemistry