This reaction goes through relatively independent two steps. In the first step, AgNTf2 convert siloxy-alkyne 1 and amide 2 into ketene INT3A-1 and silyl-imine INT3B (scheme 2). In the second step, AgNTf2 promote nucleophilic addition between ketene INT3A-1 and silylimine INT3B, following with a silylium ion migration to afford final product. If the hydrogen atom of ketene was changed into halogen or other groups, this reaction may also take place, and the regio-selective is steric-controlled (scheme 3a). Synthesizing substituted-ketenes has been extensively studied , and silyl-imines can be easily obtained (One of the feasible approaches is reaction between Chlorotriisopropylsilane (ClTIPS) and amide with base as catalyst in low temperature). So, our calculation provides a general approach to obtain substituted enamides (Scheme 3). Note that the barrier of INT3b tautomerize into INT3b-1 through intramolecular TIPS migration is only 22.8 kcal/mol (figure , with INT4a as reference point), once the thermodynamically more stable INT3b-1 is formed, the barrier of reverse reaction lead to INT3b is as high as 31.8kcal/mol, which means that the smallest substituent R7 of ketene A-INT3A-1 should not be too large to ensure formation of Z-A-3 is kinetically more favored (Scheme 3a). In the Z-TS4 and E-TS4 (figure ), the movement of methylene of 2a is constrained by fivemembered ring, which also increase steric effect, the noncyclic silyl-imine may be better tolerated in this rection.