Transition-metal-free radical phosphorylation/cyclization of unactivated alkenes: Access to phosphine-containing quinazolinones

(NH4)2S2O8 promoted tandem radical cyclization of quinazolin-4(3H)-ones with oxamic acids for the construction of fused quinazolinones under metal-free conditions

“…Using this strategy, 2,3-fused five- and six-membered rings have been synthesized successfully, with various substituents including chloroalkyl, fluoroalkyl, nitrile, sulfonyl, alkyl, and phosphine oxide groups (Scheme 1b). 8…”

Cu2O-catalyzed cascade phosphinylation/cyclization of 2′-aminochalcones for the synthesis of hemi-indigo derivatives

“…19 However, most studies have focused on the phosphorylation of specific sites on the substrates, while there are relatively few methods for phosphorylation followed by cyclization. 20 To the best of our knowledge, there are no reported examples of synthesizing phosphoryl hemi-indigo derivatives through the reaction of 2′-aminochalcones with P(O)H compounds. Therefore, we envisioned the potential of phosphorylating the double bond of chalcones initially, followed by intramolecular cyclization to yield hemi-indigo derivatives.…”