Highly regio- and stereoselective synthesis of α-(N-Alkyl-N-p- toluenesulfonyl)-β-bromo-ketones via Ni(OAc)2-catalyzed aminobromination of chalcones

Abstract

The combinations of N-methyl-p-toluenesulfonamide/NBS and N-ethyl-p-toluenesulfonamide/NBS were found to be good nitrogen/halogen resources for the aminohalogenation of α,β-unsaturated ketones in the presence of Ni(OAc)2 as the catalyst for the synthesis of vicinal haloamino ketone derivatives. The introduction of N-alkyl groups to the nitrogen resources resulted in excellent regio- and stereoselectivity for both electron-donating and electron-withdrawing group-attached unsaturated ketone substrates. The structure of the resulting products has been unambiguously confirmed by X-ray crystal structure analysis. © 2010 John Wiley & Sons A/S.