Intermediate 109A (0.0887 g, 0.283 mmol) was dissolved in tetrahydrofuran (1 mL) in a 25 mL 1 neck pear shaped flask that was equipped with a magnetic stirrer and an Ar inlet. Ethynylmagnesium bromide (5.66 mL, 2.83 mmol) was added dropwise and the reaction mixture was stirred at 35° C. for 4 h. The reaction mixture was cooled to rt, quenched with sat'd. aq NH4Cl (5 mL) and extracted with EtOAc (2×10 mL). The organic phases were combined and concentrated in vacuo. The residue was purified by silica gel chromatography (24 g silica gel, eluted with 0-100% EtOAc in hexanes) to give the desired product (0.06 g, 78%) as an orange solid. LCMS Anal. Calc'd for C12H14N2O2 278.1, found [M+H] 279.0.
