Silver(I)-Mediated Phosphorylation/Cyclization Cascade of <i>N</i>‑Cyanamide Alkenes for Divergent Access to Quinazolinones and Dihydroisoquinolinones

A silver­(I)-mediated phosphorylation/cyclization radical cascade of N-cyanamide alkenes has been developed. The addition of in situ generated phosphorus radical to N-cyanamide alkenes triggers the cascade, resulting in late-stage cyclization toward divergent access to 4-quinazolinones and dihydroisoquinolinones. Both terminal and internal N-cyanamide alkenes are applicable in this protocol, and the cyclizations are consistent with Baldwin’s rule.