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Urea‐Promoted Metal‐Free Homolytic Alkynyl Substitution (HAS): Metal‐Free C−C Coupling of Alkynyl Bromides Formed In Situ from 1,1‐Dibromoalkenes
Author(s) -
Morri Ashok K.,
Thummala Yadagiri,
Ghosh Subhash,
Doddi Venkata R.
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202100243
Subject(s) - homolysis , chemistry , radical , alkyne , aryl , medicinal chemistry , sonogashira coupling , substitution reaction , photochemistry , reagent , organic chemistry , palladium , catalysis , alkyl
Herein, the unique method reports the efficacy of abundantly available urea for the generation of alkynyl radicals from 1‐bromoalkynes under metal‐free conditions. Urea as a sole reagent enabled the transformation of 1,1‐dirbomoalkenes or 1‐bromoalkynes to 1,3‐diynes via Homolytic Alkynyl Substitution (HAS). Urea further showed efficiency in synthesizing disubstituted alkyne via Sonogashira type cross‐coupling of 1,1‐dibromalkene/1‐bromoalkyne with aryl iodide. The Azobisisobutyronitrile (AIBN) trap detected the existence of short‐lived alkynyl radical during the reaction. This method might be the first report with Homolytic Alkynyl Substitution under metal‐free conditions, whereas Homolytic Aromatic Substitution is well reported.