A mixture of Example 1 step b (234 mg, 0.52 mmol), copper (I) iodide (9 mg, 0.052 mmol), 1,10-phenanthroline (19 mg, 0.104 mmol), cesium carbonate (335 mg, 1.04 mmol) and trans-4-boc-aminocyclohexanol (560 mg, 2.6 mmol) in toluene (3 mL) was heated at 110° C. for 72 h under an argon atmosphere. The suspension was cooled to RT, diluted with EtOAc (10 mL) and filtered through HiFlo. The filtrate was concentrated in vacuo and the residue purified by reverse phase preparative HPLC (Method 3) to afford the title compound (205 mg, 39%) as an off-white solid. LCMS (Method 2): Rt 2.53 min, m/z 538 [MH+].
