Direct synthesis of 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone containing chroman-4-ones via a silver catalyzed radical cascade cyclization reaction. (6th August 2021)

• Record Type: Journal Article
• Authors: Sharma, Suraj; Sarma, Bipul; Baishya, Gakul
• Is Part Of: New journal of chemistry. Volume 45:Number 34(2021)
• Page Start: 15475
• Page End: 15486
• Publication Date: 2021-08-06
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d1nj03437e
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A novel AgNO3 /K2 S2 O8 catalyzed radical cascade cyclization reaction of 2-(allyloxy)arylaldehydes with 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone produces two new series of chroman-2-ones. Abstract : For the first time, we report a novel silver catalyzed radical cascade cyclization reaction of 2-(allyloxy)arylaldehydes to synthesize two new libraries of chroman-4-ones by using 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone as radical precursors. AgNO3 /K2 S2 O8 acts as an efficient oxidizing system and smoothly drives the reaction producing the 4-hydroxycoumarins and 4-hydroxy-6-methyl-2-pyrone containing chroman-4-ones in moderate to good yields. The protocol also makes different chemoselective products while using 2-(but-3-en-1-yloxy)benzaldehydes as radical acceptors. We have confirmed the participation of radicals by performing various radical trapping experiments with 2, 2, 6, 6-tetramethylpiperidine-1-oxyl, butylated hydroxytoluene, and diphenyl ethylene.