A straightforward, efficient, andreliable approach to syntheticallyvaluable 2,3-dihydrofurans via a reaction between Corey ylide andα,β-unsaturated ketones has been developed. The use ofsimple and widely spread starting materials as well as mild reactionconditions and scalability provide a ...
有两种可能的历程生成膦ylide中间体,一种通过三元环过渡态转化为叶立德,另一种亚磷酸酯进攻硫原子得到卡宾,然后与另一分子的亚磷酸酯反应生成叶立德中间体,最后裂环放出二氧化碳,得到烯烃。 反应实例 【J. Am. Chem. Soc.1965,87,934-935】 【Tetrahedron Lett.1996,37, 856...
Reaction of Corey Ylide with α,β-Unsaturated Ketones: Tuning of Chemoselectivity toward Dihydrofuran Synthesisfuran derivativesring closure reactionsA ... Alexey,O.,Chagarovsky,... - 《Cheminform》 被引量: 4发表: 2014年 ChemInform Abstract: (3 + 2) Annulations Between Indoles and α,β‐Unsatu...
1 Ylide precursor: Ph3P+ Br− 219 KHMDS, PhMe, −78 °C to r.t., 16 h 100%, Z only 2 Ylide precursor: Ph3P+ Br− 220 KHMDS, THF-CH2Cl2, −78 °C to r.t., 8 h 80%, Z only 3 Ylide precursor: Ph3P+ I− 146 NaHMDS, THF, −78 °C 62%, Z only 4...
The reaction typically involves the treatment of a ketone or aldehyde with a Wittig reagent, which is a phosphorus ylide. This Wittig reagent is generated by the reaction of a phosphonium salt with a strong base, such as sodium hydride. The Wittig reagent then attacks the carbonyl carbon of ...
Variants of the Johnson–Corey–Chaykovsky reaction, where a carbonyl compound is reacted with asulfur ylideto form an epoxide, have continued to be utilized by various groups. In 2009, the Aube group (Scheme 93) showed that highly constrained spiro-epoxyamines can be furnished from ε-lactams...
摘要: The CoreyChaykovsky reaction entails the reaction of a sulfur ylide, either dimethylsulfoxonium methylide 1 (Corey′s ylide) or dimethylsulfonium methylide 2, with electrophile 3 such as carbonyl, olefin, imine, or thiocarbonyl, to offer 4 as the corresponding epoxide, cyclopropane, aziridine...
Reaction of a Cyclic Oxosulfonium Ylide with Acetates of the Baylis-Hillman Adducts:Tandem Michael-Intramolecular Corey-Chaykovsky Reactions. Akiyama, H.,Fujimoto, T.,Ohshima, K.,Hoshino, K.,Yamamoto, I.,Iriye, R. Organic Letters . 1999...
The key step of the diolefination reaction involves a [2,3]-sigmatropic rearrangement of the ylide to a y-unsaturated sulfoxide with a barrier of 9.9 kcal/mol (螖H298, MP2/cc-pVDZ, for the cycloheptane derivative). The elimination of sulfenic acid from the 纬-unsaturated sulfoxide in the...
内容提示: 157Corey Chaykovsky reaction The Corey Chaykovsky reaction entails the reaction of a sulfur ylide, either di-methylsulfoxonium methylide 1 (Corey’s ylide) or dimethylsulfonium methylide 2, with electrophile 3 such as carbonyl, olefin, imine, or thiocarbonyl, to offer 4 as the ...