MECHANISTIC STUDIES AND APPLICATIONS OF AMINOHALOGENATION OF OLEFINS

Abstract

The aminohalogenation reaction is one of the most straightforward transformations that introduce both the amine and halogen moieties directly onto an unsaturated C-C bond. These vicinal haloamines are versatile synthetic intermediates and the development of efficient synthetic methodologies to afford easy access to these haloamines is thus of great interest to organic chemists. In this thesis, we detailed our discovery of two catalyst-free and metal-free alkene aminobromination protocols using a combination of N-bromosuccinimide and sulfonamide. While the aminobromination proceeded in a Markovnikov fashion to give the β-bromoamide product under ambient conditions, small changes in the reaction atmosphere and temperature triggered a complete switch in regioselectivity to give the opposite regioisomer α-bromoamide. Our mechanistic studies revealed that the two reactions followed distinctly different mechanistic pathways, with each involving a different active brominating species, to give the respective regioisomers. In addition, the development of a carbamate-catalyzed enantioselective bromolactamization of olefinic amides has also been achieved, giving bromolactam products of high enantioselectivities.