This work describes a straightforward diastereoselective synthetic access to azirino[2,1-b]benzo[e][1,3]oxazines containing phosphorus substituents such as phosphonate or phosphine oxide, by means of nucleophilic addition of functionalized phenols to the C-N double bond of 2H-azirine derivatives. In addition, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549) and human embryonic kidney (HEK293) was also screened. Some azirino[2,1-b]benzo[e][1,3]oxazines 4 and 6 exhibited very good activity against the A549 cell line in vitro. Furthermore, selectivity towards cancer cell (A549) over (HEK293), and non-malignant cells (MCR-5) has been detected.