Tetrahydrofuran → 6-Anthracen-9-ylmethylene-1-(4-fluoro-phenyl)4a-methyl-1,4,4a,6,7,8-hexahydro-benzo[f]indazol-5-one

In a 100 mL round bottom flask, aldehyde (207) (100 mg, 0.337 mmol) and anthracene-9-carboxaldehyde (349 mg, 1.69 mmol) were dissolved in 10 mL THF and cooled to 0° C. Lithium hexamethyldisilylamide (LHMDS) (370 μL, 0.370 mmol) was added dropwise, and the solution was stirred at room temperature for 16 hours. The reaction was quenched with 5 mL of saturated aqueous ammonium chloride. The aqueous layer was extracted with ether (3×10 mL), and the pooled organic extracts were washed with brine (10 mL), dried (MgSO4) and then concentrated. Flash chromatography of the residue (0-25% EtOAc/hexanes) gave (269) (127.9mg, 78%).