1256285-94-5Relevant academic research and scientific papers
Iodine-mediated solvent-controlled selective electrophilic cyclization and oxidative esterification of o-alkynyl aldehydes: An easy access to pyranoquinolines, pyranoquinolinones, and isocumarins
Verma, Akhilesh K.,Rustagi, Vineeta,Aggarwal, Trapti,Singh, Amit P.
, p. 7691 - 7703 (2010)
Chemoselective behavior of iodine in different solvents in the electrophilic iodocyclization of o-alkynyl aldehydes is described. o-Alkynyl aldehydes 3a-t on reaction with I2 in CH2Cl2 with appropriate nucleophiles provides pyrano[4,3-b]quinolines 4a-f, via formation of cyclic iodonium intermediate Q; however, using alcohols as a solvent as well as nucleophile, o-alkynyl esters 5a-y were obtained selectively in good to excellent yields via formation of hypoiodide intermediate R. Subsequently, o-alkynyl esters were converted in to pyranoquinolinones 6a-i and isocoumarin 6j by electrophilic iodocyclization. This developed oxidative esterification provides a novel access for the chemoselective synthesis of esters 5q-u from aldehydes 3n-p without oxidizing primary alcohol present in the substrate.
