A non‐oxidant and metal‐free strategy for synthesizing iso‐coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o‐(1‐alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by‐products in the batch processes, but also help to overcome
Synthesis of selenated isochromenones by AgNO<sub>3</sub>-catalyzed three-component reaction of alkynylaryl esters, selenium powder and ArB(OH)<sub>2</sub>
We reported AgNO3-catalyzed three-component reaction of alkynylaryl esters, selenium powder and ArB(OH)2, providing an efficient synthetic route to selenated isochromenones.
Nucleophilic Cyclization of<i>o</i>-Alkynylbenzamides Promoted by Iron(III) Chloride and Diorganyl Dichalcogenides: Synthesis of 4-Organochalcogenyl-1<i>H</i>-isochromen-1-imines
作者:Jose S. S. Neto、Davi F. Back、Gilson Zeni
DOI:10.1002/ejoc.201403534
日期:2015.3
4-organochalcogenyl-1H-isochromen-1-imines in good yields and with good selectivities. The reaction took place with 0.5 equiv. of the diorganyl dichalcogenides, which demonstrates that both halves of the diorganyl dichalcogenides (RYYR 2RY) were incorporated into the final product. Mechanistic studies suggested that the regioselectivity of the cyclization is governed by a seleniranium ion, a key intermediate formed
Synthesis of Isocoumarins and α-Pyrones via Electrophilic Cyclization
作者:Tuanli Yao、Richard C. Larock
DOI:10.1021/jo034308v
日期:2003.7.1
A variety of substituted isocoumarins and alpha-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICI, I-2, PhSeCl, p-O2NC6H4SCl, and HI. This methodology accommodates various alkynyl esters and has been successfully extended to the synthesis of polycyclic aromatic and biaryl compounds.
Regioselective Synthesis of Isochromenones by Iron(III)/PhSeSePh-Mediated Cyclization of 2-Alkynylaryl Esters
作者:Adriane Sperança、Benhur Godoi、Simone Pinton、Davi F. Back、Paulo H. Menezes、Gilson Zeni
DOI:10.1021/jo201211s
日期:2011.8.19
A series of 4-Se-(Te, S)-isochromenones and 3-substituted isochromenones were synthesized in good yields via FeCl3-mediated cyclization of alkynylaryl esters with different diorganyl dichalcogenides. This methodology was carried out at room temperature, using inexpensive and environmentally friendly iron salts as metallic source and under air atmosphere. The reaction showed to be tolerant to a range of substituents bonded into the aromatic ring of the diorganyl dichalcogenides as well as to alkyl groups directly bonded to the chalcogen atom. Alternatively, the cyclization reaction of 2-alkynylaryl esters with FeCl3, in the absence of diorganyl dichalcogenide, gave the isochromenones without the chalcogen moiety in the structure. This approach proved to be highly regioselective, providing only six-membered ring products, once the possible five-membered products were not observed in any experiments.