The general procedure for the synthesis of 4-(1-Boc-4-piperidinyl)phenylboronic acid pinacol ester from 1-N-Boc-4-(4-bromophenyl)piperidine and pinacol ester of boronic acid was as follows: in a pressure tube, a dioxane solution of tert-butyl 4-(4-bromophenyl)piperidine-1-carboxylate (1363 mg, 4.006 mmol) was purified with bis(pinacolato)diboron (1526 mg , 6.009 mmol), KOAc (1179 mg, 12.02 mmol) and PdCl2(dppf)-DCM (327.1 mg, 0.4006 mmol) treatment. The mixture was bubbled with nitrogen for 1 min, then sealed and heated at 100 °C overnight. After the reaction mixture was cooled to ambient temperature, it was diluted with a mixture of EtOAc (75 mL), water (50 mL), and brine (25 mL), and the resulting emulsion was filtered through Celite and washed with EtOAc. The two-phase filtrate was separated and the organic phase was washed with brine, dried (MgSO4), filtered and concentrated in vacuum. Purification of the crude product by silica gel chromatography (0-50% EtOAc/hexane) afforded 4-(1-Boc-4-piperidinyl)phenylboronic acid pinacol ester (1437 mg, 93% yield).1H NMR (CDCl3) δ 7.76 (d, 2H), 7.22 (m, 2H), 4.24 (d, 2H), 2.79 (dt, 2H), 2.65 ( tt, 1H), 1.81 (m, 2H), 1.63 (dq, 2H), 1.48 (s, 9H), 1.33 (s, 12H).
