Powerful Lewis Acid Catalyst

　N-(Trimethylsilyl)bis(trifluoromethanesulfonyl)imide (1) is an analogue of, TMSOTf and TMSN(SO₂F)₂, which has very low electron density on its silicon atom and acts as powerful Lewis acid catalyst in various reactions. For example, Mathieu et al. used 1 for Diels-Alder reaction using acrylates as dienophiles, to afford the corresponding addition products in high yields under mild conditions.¹⁾
　Furthermore, Mikami et al. and Ishihara et al. applied 1 to Friedel-Crafts alkylation²⁾ and Mukaiyama aldol reactions,³⁾ respectively, and both groups reported the utility of 1 as an excellent Lewis acid catalyst.