transition‐metal‐free carboarylation of alkynes with commercial and readily available alcohols as alkylating agents was realized in the presence of an environmentally benign calcium catalyst. Thereby, a novel protocol for the one‐step synthesis of highly congested, all‐carbon tetrasubstituted alkenes, as incorporated in potentially bioactive, complex dihydronaphthalene, chromene and dihydroquinoline
Metal-Free Electrophilic Phosphination/Cyclization of Alkynes
作者:Yuto Unoh、Koji Hirano、Masahiro Miura
DOI:10.1021/jacs.7b02977
日期:2017.5.3
A metal-free electrophilicphosphination reaction has been developed. Electrophilic phosphorus species generated in situ from secondary phosphine oxides and Tf2O smoothly couple with alkynes possessing pendant nucleophiles to afford the corresponding phosphinated cyclization products in good yield. Preliminary NMR studies show that phosphirenium species may be involved as intermediates of the cyclization
Metal‐Free Synthesis of Selenodihydronaphthalenes by Selenoxide‐Mediated Electrophilic Cyclization of Alkynes
作者:Shaoyu An、Zhong Zhang、Pingfan Li
DOI:10.1002/ejoc.202100423
日期:2021.6.7
A metal-free, one-pot selenium mediated electrophiliccyclization reaction of alkynes and triflic anhydride-activated selenoxides was realized, giving selenium containing dihydronaphthalene products, including selenium-substituted phenanthrene, dihydroquinoline, 2H-chromene, and coumarin.
Ligand exchange reaction of sulfoxides in organic synthesis: A novel method for synthesizing acetylenes and allenes from carbonyl compounds through sulfoxides having a trifluoro-methanesulfonyloxy group on the β-carbon
A novel method for synthesizing acetylenes and allenes from carbonyl compounds is described. Ligand exchange reaction of alkenylsulfoxides having a trifluoromethanesulfonyloxy group on the β-carbon, which were derived from α-alkyl β-ketosulfoxides, with n-BuLi gave disubstituted acetylenes in good yields. In the case of alkenylsulfoxides having both the trifluoromethanesulfonyloxy and aryl groups on
Formation of C(sp<sup>2</sup>)Boronate Esters by Borylative Cyclization of Alkynes Using BCl<sub>3</sub>
作者:Andrew J. Warner、James R. Lawson、Valerio Fasano、Michael J. Ingleson
DOI:10.1002/anie.201505810
日期:2015.9.14
BCl3 is an inexpensive electrophile which induces the borylativecyclization of a wide range of substituted alkynes to regioselectively form polycycles containing synthetically versatile C(sp2)boronateesters. It proceeds rapidly, with good yields and is compatible with a range of functional groups and substitution patterns. Intermolecular 1,2‐carboboration of alkynes is also achieved usingBCl3 to