Step D To pinacol diboronate (250 mg, 0.986 mmol), potassium acetate (242 mg, 2.466 mmol) and PdCl2(dppf)-CH2Cl2 adduct (67 mg, 0.082 mmol) in a thick-walled tube was added a solution of 3-(4-bromophenyl)-3-methylthietane 1,1-dioxide (226 mg, from Step C) in DMF (5 ml). The tube was flushed with N2, then capped and heated to 90° C. for 4 hours. Then the reaction was cooled to RT and diluted with EtOAc (30 ml) and water (20 ml). The aqueous layer was separated and extracted with EtOAc (25 ml). The combined organic layers were washed with water (50 ml), dried (Na2SO4), filtered and concentrated. The resulting crude material was purified by Isco™ system, 40 g gold cartridge, 40 ml flow rate, gradient—0/100 (1 min) to 50/50 (19 min) to 50/50 (21 min—total run time) of EtOAc/hexanes. The fractions containing the product were combined and concentrated to provide 3-methyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)thietane 1,1-dioxide as a white solid.
