4-Piperidin-4-ylbenzoic acid methyl ester (0.40 g, 1.81 mmol), palladium(II) acetate (0.015 g, 0.069 mmol) sodium tert-butoxide (0.34 g, 3.44 mmol) and BINAP (0.06 g, 0.096 mmol) were added to a stirred solution of intermediate D3 (0.31 g, 1.37 mmol) in toluene (10 ml). The reaction mixture was heated at 100° C. for 16 hours in a sealed tube. After cooling to room temperature the mixture was diluted with EtOAc and then filtered through diatomaceous earth, after which the solvent was evaporated in vacuo. The crude residue was treated with a mixture of DCM/methanol and then filtered off. The filtrate was evaporated to dryness in vacuo to yield crude D37 (0.48 g, 100%) that was used without further purification.
