Ionic Liquid, 1‐ n ‐Butyl‐3‐methylimidazolium Bis(trifluoromethanesulfonyl)imide, Resulted in the First Catalyst‐Free Aminohalogenation of Electron‐Deficient Alkenes

The 2‐Ns‐based aminohalogenation of α,β‐unsaturated ketones has been achieved in an ionic liquid, 1‐ n ‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide {[bmim][N(SO 2 CF 3 ) 2 ]}. [Bmim][N(SO 2 CF 3 ) 2 ] was found to be superior not only to classical organic solvents but also to its counterpart, [bmim][BF 4 ], which was proven to be successful in the TsNCl 2 ‐based aminohalogenation but failed to give any product for this reaction. The present process takes the advantage of 2‐NsNCl 2 as the stable nitrogen/halogen source in a one‐pot operation without the use of any metal catalysts, it is convenient to perform without special protection of inert gases. Eight examples were examined with good to excellent stereoselectivity (1:5 to one isomer) and modest to good chemical yields (53–72 %).