摘要
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 withπ-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.
作者
王恒定
江凌
梁鸿雁
樊红军
Wang Hengding;Jiang Ling;Liang Hongyan;Fan Hongjun(State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,Liaoning 116023;University of Chinese Academy of Sciences,Beijing 100864;Technical Center,Xining Special Steel Co Ltd.,Xining 810005)
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2021年第11期4327-4337,共11页
Chinese Journal of Organic Chemistry
基金
国家重点研发计划(No.2016YFB0600301)
国家自然科学基金(92061114,21873096)
中科院战略先导计划(No.XDB17010200)资助项目.
