Zinc Triflate as Lewis Acid in Nucleophilic Addition to Cyclic<i>N</i>-Acyliminium Ions
作者:Ronaldo Aloise Pilli、Luís Gustavo Robello
DOI:10.1055/s-2005-872659
日期:——
Zinc triflate-mediated nucleophilicaddition of allytrimethylsilane, silyl enol ethers and terminal acetylenes to cyclic N-acyliminium ions at room temperature in CH 2 Cl 2 is described. The corresponding α-substituted heterocycles were obtained in moderate to good yields. The versatility of this reagent was demonstrated in the one-pot generation of the N-acyliminium ion and the zinc alkynylide species
methodology for the C(sp3)−C(sp3) functionalisation of saturated N-heterocyclic systems is disclosed. First, aminal derivatives are generated through the anodic oxidation of readily accessible carboxylic acids. Then, in the presence of BF3 ⋅ OEt2, iminium ions are unmasked and rapidly alkylated by organozinc reagents under flow conditions. Secondary, tertiary and quaternary carbon centers have been successfully
Catalytic Ring Expansion of Cyclic Hemiaminals for the Synthesis of Medium‐Ring Lactams
作者:Wanxiang Zhao、Hui Qian、Zigang Li、Jianwei Sun
DOI:10.1002/anie.201504926
日期:2015.8.17
A mild and efficient intermolecular ring‐expansion approach was developed for the synthesis of medium‐ringlactams by using siloxy alkynes. Key to success is the suitable combination of a superior catalyst and an exceptional nitrogen‐protecting group. Control experiments indicated that the reaction is remarkably selective toward the desired lactam formation, even with many possible non‐productive pathways
Parallel Electrosynthesis of<i>N</i>-Acyliminium Ion Equivalents Using Silica Gel-supported Piperidine
作者:Toshiki Tajima、Atsushi Nakajima
DOI:10.1246/cl.2009.160
日期:2009.2.5
Parallel anodic methoxylation of carbamates was successfully carried out to provide the corresponding α-methoxylated products as N-acyliminium ion equivalents in high to excellent yields using silica gel-supported piperidine (Si–piperidine).
Electrochemical Scaled‐up Synthesis of Cyclic Enecarbamates as Starting Materials for Medicinal Chemistry Relevant Building Bocks
作者:Oleksandr D. Tereshchenko、Maryana Y. Perebiynis、Irina V. Knysh、Olesia V. Vasylets、Anna A. Sorochenko、Eugeniy Y. Slobodyanyuk、Eduard B. Rusanov、Oleksandr V. Borysov、Sergey V. Kolotilov、Sergey V. Ryabukhin、Dmitriy M. Volochnyuk
DOI:10.1002/adsc.202000450
日期:2020.8.4
The electrochemical Shono oxidation of Boc‐protected cyclic amines was revised. The conditions for scalable electrochemicalsynthesis of cyclic enecarbamates were found. The developed protocol included recycling of the full range of used reagents, favoring to E‐factor reduction according to Green Chemistry requirements. The method opened the way for the convenient preparation of previously uncommon