Chiral Auxiliary Induced Asymmetric Synthesis Of Amines Containing Triflyl Group

The radius of fluorine atom is similar to the hydrogen atom,and the fluorine atom has the strongest electronegativity and low polarizability.The introdution of fluorine atom often changes the pharmacological properties of biologically active molecules.Fluorine containing compounds have been widely used in pesticide,medicine and material during the past decades.On the other hand,compounds containing chiral sulfonyl groups are playing an increasingly important role in medicinal chemistry because its structure is similar to carbonyl moiety.Therefore,we explored the asymmetric synthesis of amines containing triflyl induced by(S)-tertbutanesulfinamide.Firstly,(S)-N-tert-butanesulfinamide and aldehyde or ketone were condensed to afford imines,then the asymmetric nucleophilic addition of the resulting imine with ?-sulfonyl carbanions was explored.The diastereoselectivity of the reaction was controlled by the chiral auxiliary.After optimization of the reaction conditions including base,solvent,additive,temperature and reaction time etc,the desired product can be obtained in moderate to good yields(45~78%)and moderate diostereoselectivity.The absolute configuration of the major product is determined by X-ray single crystal analysis.Electronic effect and steric effect influence the reaction directly,and benzylic triflyls with strong electron withdrawing group substitutent and aromatic imines are not suitable for the reaction.Finally,the chiral tert-butanesulfinyl group could be readily cleaved under mild acidic condition in excellent yield of 92%.