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Cyclization of Homopropargyl Chalcogenides by Copper(II) Salts: Selective Synthesis of 2,3‐Dihydroselenophenes, 3‐Arylselenophenes, and 3‐Haloselenophenes/thiophenes
Author(s) -
Schumacher Ricardo F.,
Rosário Alisson R.,
Leite Marlon R.,
Zeni Gilson
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302129
Subject(s) - chemistry , dichloroethane , sonogashira coupling , dimethylacetamide , copper , halide , solvent , 1,2 dichloroethane , medicinal chemistry , combinatorial chemistry , organic chemistry , palladium , catalysis
Copper(II) halide mediated cyclization of homopropargyl chalcogenides gave three types of chalcogenophene derivatives. Selective product formation was achieved by controlling solvent, temperature, and atmosphere. By using CuBr 2 and 1,2‐dichloroethane at room temperature under ambient atmosphere, 4‐bromo dihydroselenophene derivatives were obtained, whereas CuBr 2 and 1,2‐dichloroethane at reflux gave selectively 2‐substituted selenophenes. When 1,2‐dichloroethane was replaced by dimethylacetamide, 3‐halo‐selenophenes were obtained exclusively. The versatility of chalcogenophenes was also studied by reaction of 3‐haloselenophenes with terminal alkynes under Sonogashira conditions affording the cross‐coupled products. In addition, the reaction of 3‐haloselenophenes with boronic acids gave the corresponding Suzuki‐type products in good yields.