Direct Catalytic Asymmetric Synthesis of N-Heterocycles from Commodity Acid Chlorides by Employing α,β-Unsaturated Acylammonium Salts
作者:Sreekumar Vellalath、Khoi N. Van、Daniel Romo
DOI:10.1002/anie.201306050
日期:2013.12.16
Taming the beast, asymmetrically: Modulation of the reactivity of acidchlorides, using cinchona alkaloid catalysts, results in chiral α,β‐unsaturated acylammoniums, which react with nucleophiles enantioselectively to give pyrrolidinones, piperid‐2‐ones, and dihydropyridinones. This nucleophile‐catalyzed Michael/proton transfer/lactamization or lactonization organocascade leads to chiral intermediates
Rapid synthesis of substituted pyrrolines and pyrrolidines by nucleophilic ring closure at activated oximes
作者:Nandkishor Chandan、Amber L. Thompson、Mark G. Moloney
DOI:10.1039/c2ob26423d
日期:——
Substituted pyrrolines are available by ringclosure initiated by direct nucleophilic attack of stabilized enolates at the nitrogen of oximes activated with a leaving group, in a process which effectively out-competes the more usual Beckmann rearrangement. Subsequent reduction provides diastereoselective access to the corresponding pyrrolidines. This provides a rapid route to saturated heterocyclic
Atom-economic thiophosphoroselenenylations of C–H acid esters and amides
作者:Arkadiusz Majewski、Witold Przychodzeń
DOI:10.1080/00397911.2021.1971719
日期:2021.11.17
possible to utilize both equivalents of the selenenylating agent. The procedures work well for the majority of nucleophiles in a pKa range between more acidic malononitrile or Meldrum acid and less acidic phenylacetates. The reaction carried out on diethylmalonate in boiling rectified ethanol yields selenoacetate, which cannot be obtained by direct phosphoroselenenylation. Crystal structure of one of the
challenging to prepare, especially in opticallyactive form. A Michael addition/proton transfer/lactamization organocascade process is described that delivers medium‐sized lactams, including azepanones, benzazepinones, azocanones, and benzazocinones, in high enantiopurity through the intermediacy of chiral α,β‐unsaturated acylammonium salts. An unexpected indoline synthesis was also uncovered, and the benzazocinone
Reaction of non-activated olefins with CH-acids; a novel method for the preparation of electrophilic cyclopropanes
作者:László Tóke、Gábor T Szabó、Zoltán Hell、Gábor Tóth
DOI:10.1016/s0040-4039(00)88529-9
日期:1990.1
Reaction of non-activated olefines with active methylene compounds was accomplished under solid-liquid phase-transfer conditions, in the presence of iodine, to give electrophiliccyclopropanes of a wide range of substituents. Several data to the mechanism of the reaction are also given.