Phosphine-Mediated Morita–Baylis–Hillman-Type/Wittig Cascade: Access to E‑Configured 3‑Styryl- and 3‑(Benzopyrrole/furan-2-yl) Quinolinones

A phosphine-mediated, well-designed Morita–Baylis–Hillman-type/Wittig cascade for the rapid assembly of a quinolinone framework from benzaldehyde derivatives is developed for the first time. By rationally combining I₂/NIS-mediated cyclization, biologically relevant 3-(benzopyrrole/furan-2-yl) quinolinones were facilely synthesized in a one-pot process by starting from 3-styryl-quinolinones bearing an o-hydroxy/amino group, significantly expanding the chemical space of this privileged skeleton. Further utility of this protocol is illustrated by successfully performing this transformation in a catalytic manner through in situ reduction of phosphine oxide by phenylsilane.