银离子可以高效地催化硅烷氧基炔与α,β-不饱和羰基化合物之间的[2+2]环加成反应,在银离子催化下硅烷氧基炔可以与甲醛的羰基发生[2+2]环加成后开环生成不饱和酯.利用密度泛函理论(DFT)计算发现,在这两个反应中银离子与硅烷氧基炔之间相互作用,将硅烷氧基炔激活成为硅正离子和银烯酮,硅正离子进一步催化羰基化合物(α,β-不饱和羰基化合物或者醛)和银烯酮之间的[2+2]环加成反应.“,”Mechanism of silver-catalyzed[2 + 2]cycloaddition between siloxy-alkynes and α,β-unsaturated carbonyl compound remains controversial.Based on density functional theory (DFT) calculation,it is revealed that Ag+ activate siloxy-alkyne into silver-ketene and silylium ion (TIPS+) in this reaction.TIPS+ then promote[2+2]cycloaddition between α,β-unsaturated carbonyl compound and silver-ketene to form cyclobutane-intermediate,which undergos TIPS+ migration and transforms into final product.The mechanism of Ag+ catalyzed olefination of aldehydes using siloxy-alkynes was also investigated,the results showed that TIPS+ migration also took place in this reaction.In the two reactions studied,Ag+interacts with π-bond of siloxy-alkynes and triggers TIPS+ migration,which offers alternative solution to silylium-catalyzed reaction.As similarity of ynolates,silver-ketenes are more stable,which can undergo 1,4-nucleophilic addition with α,β-unsaturated compound.For[2+2]cycloaddition,catalytic variant is rather limited,this work provides a different perspective to obtain four-membered ring products or its ring-open derivates.