Synthesis of Enol Lactones via Cu(I)-Catalyzed Intramolecular O-Vinylation of Carboxylic Acids
作者:Changhui Sun、Yewen Fang、Shuang Li、Yue Zhang、Qiwu Zhao、Shana Zhu、Chaozhong Li
DOI:10.1021/ol9015578
日期:2009.9.17
catalysis of CuI/trans-N,N′-dimethylcyclohexane-1,2-diamine, a number of carboxylic acids underwent efficient intramolecular O-vinylation with vinyl bromides leading to the synthesis of the corresponding five- and six-membered enollactones. The same catalytic system also led to the efficient cycloisomerization of alkynoic acids.
The synthesis of β‐keto lactone was completed using cyclohexanone as starting material. The α,β‐unsaturated lactone was obtained through Reformatsky reaction and iodolactonization. The aforementioned lactone was converted into target compound 1 (β‐keto lactone) by Nef oxidation and Claisen condensation in six steps with 17.9% overall yield.
By treatment with stabilized lithium phosphonates in the presence of activated 4Å molecular sieves, unprotected α-hydroxy ketones 1 undergo a convenient Horner-Wadsworth-Emmonsolefination to give directly butenolides 3 as exclusive or predominant products.
Facile synthesis of unsaturated lactones via intramolecular Wittig reaction
作者:Pradeep Kumar、K. Saravanan
DOI:10.1016/s0040-4020(97)10428-8
日期:1998.3
The phosphoranes 3 formed from the reaction of a variety of keto alcohols 1 and (triphenylphosphoranylidene)ethenone 2 undergo intramolecular Wittig cyclization to afford the unsaturated lactones in moderate yields.
Reaction Of β,γ-Unsaturated Carboxylic Acids With Thallium Triacetate (Tta): Lactonization<i>VS</i>Oxidative Decarboxylation
作者:Helena M. C. Ferraz、Mčnica V. A. Grazini、Luiz F. Silva、Luiz S. Longo
DOI:10.1080/00397919908086184
日期:1999.6
Abstract The reaction of six β,γ-unsaturated carboxylic acids with thalliumtriacetate (TTA) was studied. The nature of the products is highly sensitive to the substitution pattern of the substrates. Aliphatic acids gave mainly lactones, while those bearing an aromatic ring furnished only decarboxylation products.