A mixture of Intermediate A (0.8 g, 3.01 mmol), morpholine (1.048 g, 12.03 mmol), Pd2(dba)3 (0.275 g, 0.301 mmol), xantphos (0.305 g, 0.602 mmol) and KOtBu (0.337 g, 3.01 mmol) in toluene (15 ml) was bubbled with N2 for 15 min and then was heated at 100° C. for 5 h under MW radiation. The mixture was quenched with saturated aqueous NaHCO3 solution. The aqueous phase was extracted with DCM/IPA (10 ml, v/v=3/1) for 3 times. The combined extract was dried over anhydrous MgSO4. Filtered and concentrated, the residue was purified by silica gel chromatography to afford the title compound (0.31 g, 40.3% yield). LCMS (method B): [M+H]+=231, tR=1.1 min.
