Catalytic Asymmetric Bromoamination of Chalcones

Significance

Asymmetric bromoamination of chalcones leading to α-bromo-β-amino ketones is concerned with major difficulties, such as predominate formation of α-amino-β-bromo derivatives and compromised enantioselectivity due to olefin-to-olefin transfer. In this paper, the authors have overcome these issues by development of a highly regio- and enantioselective bromoamination of chalcones mediated by scandium complex of ligand 1 and NBS/ArSO₂NH₂. Various benzenesulfonates (and MsNH₂) as well as variously substituted chalcones were tolerated. All the products were obtained with a dr of >99:1, excellent yields and enantioselectivities (up to 99% ee).