A mechanistic study of the participation of azomethine ylides and carbonyl ylides in [3+2] cycloaddition reactions. Issue 7 (18th February 2015)

• Record Type: Journal Article
• Authors: Domingo, Luis R.; Aurell, Maria J.; Pérez, Patricia
• Is Part Of: Tetrahedron. Volume 71:Issue 7(2015)
• Page Start: 1050
• Page End: 1057
• Publication Date: 2015-02-18
• Subjects: [3+2] Cycloaddition reactions -- Azomethine ylides -- Carbonyl ylides -- Molecular mechanisms -- DFT calculations; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2014.12.094
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The participation of azomethine ylides (AYs) and carbonyl ylides (CYs) in [3+2] cycloaddition (32CA) reactions has been analysed at the DFT B3LYP/6-31G(d) level. The asymmetric substitution breaks the pseudodiradical character of the simplest three-atom-components (TACs), modifying their electrophilic and nucleophilic behaviours. These TACs react quickly towards electrophilic nitroethylene. However, while the reaction with AY takes place via a zw-type mechanism, the reaction with CY appears to take place via a pr-type mechanism. A different behaviour is found in the reactivity towards the nucleophilic methyl vinyl ether. While AY presents a high activation energy, CY presents a high reactivity via a pr-type mechanism. These reactions are completely regioselective, displaying exo stereoselectivity. The present study makes it possible to establish that the substitution provokes a different reactivity pattern in these TACs; while in CYs does not substantially modify their pr-type reactivity, AYs only participate in zw-type 32CA reactions towards electrophilic ethylenes. Graphical abstract: