Synthesis of (+)-Acutiphycin

Significance

(+)-Acutiphycin, isolated from the blue-green alga Oscillatoria acutissma, displays in vivo activity against Lewis lung carcinoma and is cytotoxic toward various cancer cell lines. Noteworthy in this synthesis is (1) the three-stage, one-pot preparation of δ-lactone H, (2) an intermolecular SmI₂-mediated Reformatsky reaction and (3) macrolactonization by intramolecular ketene capture.