Reactivity of 1,3-dichloro-1,3-bis(dimethylamino)-propenium salts with primary amines

1,3-Dichloro-1,3-bis(dimethylamino)propenium salts react with primary amines to give different products depending on the structure of the amine. Reactions in which the primary amine is bonded to a tertiary carbon (tert-butylamine and 1-adamantylamine) result in 1,1-bis(dimethylamino)-3,3-bis(alkylamino)propenium salts which form via a 1,3-dimethylamino shift. In contrast, the reactions in which the primary amine is bonded to a secondary carbon (cyclohexylamine, cyclopentylamine, and sec-butylamine) result in 1-(ylidene)amino-1,3-bis(dimethylamino)propenium salts which form via an intramolecular hydride shift. All of the synthesized compounds have been fully characterized using spectroscopic methods, including single crystal X-ray diffraction. Finally, the mechanisms of the intramolecular rearrangements have been investigated computationally at the omega B97X-D/6-311G(d,p) level of theory, suggesting that the reactions proceed through putative keteniminium species.

Automated summary

In this study, 1,3-Dichloro-1,3-bis(dimethylamino)propenium salts were found to react with primary amines to give different products depending on the structure of the amine. Spectroscopic methods and computational chemistry were used to investigate the mechanisms of the reactions and the characteristics of the products.