Synthesis of 1-substituted 5-alkyl(aryl)-1,3-dihydro-2H-pyrrol-2-ones. Azocoupling with diazonium salts
摘要:
Reactions of 5-alkyl- and 5-aryl-3H-furan-2-ones with 1,3- and 1,4-binucleophiles of aromatic series were carried out for the first time under various conditions. In the presence of a base the reaction resulted in 1-R-1,3-dihydro-2.-pyrrol-2-ones, under milder conditions intermediates were isolated, 4-aryl-4-oxobutanamides. The structure of the latter was proved by spectral methods. By an example of 1-R-1,3-dihydro-2.-pyrrol-2-ones the possibility was demonstrated of their functionalization via introducing an aryldiazenyl fragment.
Palladium(II) catalyzed cyclization of alkynoic acids
作者:Claude Lambert、Kiitiro Utimoto、Hitosi Nozaki
DOI:10.1016/s0040-4039(01)81594-x
日期:——
Under the catalytic action of palladium(II) in the presence of triethylamine, 3-, 4-, and 5-alkynoic acids afford 3-buten-4-olides, 4-penten-4-olides, and 5-hexen-5-olide, respectively, in good to excellent yields.
Et3N catalyzed direct α-addition cascade isomerization of deconjugated butenolides with α-ketoesters for the synthesis of α,γ-disubstituted butenolide derivatives
γ-disubstituted butenolides are widespread occurrences in numerous pharmacologically active molecules. In this paper, a highly efficient method for the synthesis of α,γ-disubstituted butenolide derivatives via a direct α-addition cascade isomerization of deconjugated butenolides with α-ketoesters using Et3N as catalyst, has been successfully developed. A series of α,γ-disubstituted butenolides have been
α,γ-二取代丁烯内酯广泛存在于许多药理活性分子中。本文成功开发了一种以 Et 3 N 为催化剂,通过去共轭丁烯内酯与 α-酮酯直接 α-加成级联异构化合成 α,γ-二取代丁烯内酯衍生物的高效方法。一系列 α,γ-二取代丁烯内酯的产率高达 97%,具有优异的区域选择性(高达 >19/1 rr)。据我们所知,迄今为止,在直接α-加成级联异构化制备α,γ-二取代丁烯内酯中应用去共轭丁烯内酯尚无先例。
Synergistic Lewis base and anion-binding catalysis for the enantioselective vinylogous addition of deconjugated butenolides to allenoates
作者:Vikas Kumar、Santanu Mukherjee
DOI:10.1039/c3cc46858e
日期:——
An enantioselective vinylogous umpolung addition of deconjugated butenolides to allenoates has been developed for the first time with the help of synergistic combination of an achiral phosphine and a chiral squaramide, and represents the first example of a catalytic enantioselective Cγ–Cγ bond formation between two different carbonyl partners.
2-Aryl- and 2-alkylfurans are converted into the corresponding 5-organyl-2(3H)-butenolides by the oxidation of boron derivatives with m-chloroperbenzoic acid.
two‐step procedure that consists of a catalytic enantioselective vinylogousMichaeladdition of deconjugatedbutenolides to cyclopentene‐1,3‐dione and a base‐mediated decarboxylation. The overall process utilizes deconjugatedbutenolides as the source of the highly substituted vinyl unit. Five‐membered carbocycles containing a remote all‐carbon quaternarystereogeniccenter are obtained in good yields and