Ag2CO3-catalyzed difunctionalization of alkynes via a radical phosphonation and C-H functionalization tandem process was developed to synthesize various 3-phosphonated coumarins in moderate to high yields with high regioselectivity. A catalytic amount of cheap and nontoxic silver salt was employed in the domino C-P and C-C formation of alkynoates for the first time. Mechanistic studies indicate that the reaction pathway might proceed via the generation and cyclization of a phosphonated vinyl radical intermediate.
Metal-Free, Visible-Light-Promoted Synthesis of 3-Phosphorylated Coumarins <i>via</i>
Radical C−P/C−C Bond Formation
A metal‐free, visible‐light‐promoted direct difunctionalization of alkynoates was achieved undermildconditions. By employing catalytic quantities of the commercially available Eosin Y (EY) as the photocatalyst and tert‐butyl‐hydroperoxide (TBHP) as the oxidant, we developed a radical tandem phosphorylation/cyclization reaction to synthesize various 3‐phosphorylated coumarins with high functional