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Visible-Light-Mediated Vicinal Difunctionalization of Activated Alkynes with Boronic Acids: Substrate-Controlled Rapid Access to 3-Alkylated Coumarins and Unsaturated Spirocycles.

Sabyasachi MannaKandikere Ramaiah Prabhu
Published in: Organic letters (2023)
A visible-light-mediated difunctionalization of activated alkynes with boronic acid is unveiled to synthesize 3-alkylated coumarins and unsaturated spiro-lactones. The substituent at the para -position of the aryl ring of aryl alkynoate plays a pivotal role in the selective formation of chain-alkylated coumarins or spirocyclic compounds under mild conditions. The reaction employs a hypervalent iodine reagent and ruthenium photocatalyst. The spiro-lactones thus obtained were subjected to another novel mode of visible-light-mediated radical addition cascade cyclization (RACC) to access various new fused spirocyclic compounds.
Keyphrases
  • visible light
  • magnetic resonance imaging
  • magnetic resonance