To a solution of 4-chloronaphthalene-1,2-dione (1.0 g, 5.2 mmol) and tert-butyl 4-hydroxy-4-(mercaptomethyl)piperidine-1-carboxylate (1.348 g, 5.45 mmol) in acetonitrile (20 mL) was added potassium carbonate (2.16 g, 15.6 mmol). The reaction was stirred at room temperature for 2 hours. To the reaction mixture was then added EtOAc (40 mL) and the reaction mixture filtered through celite. The solvent was then removed under reduced pressure. The crude foamy residue was dissolved in EtOAc (40 mL) and the solvent once again removed under reduced pressure. To the crude foamy solid was added EtOAc (7 mL) and the reaction mixture stirred for 10 min. An orange solid separated out. Diethyl ether (20 mL) was then added and the solution was left in the refrigerator to ensure that most of the product crashed out. The solid was filtered and washed with diethyl ether to afford the product as an orange solid. The mother liquor was concentrated under reduced pressure and purified by flash column chromatography (SiO2, 40% EtOAc in hexanes) to recover the product (1.66 g, 80%) as an orange solid. M.p.=156-157° C.; 400 MHz 1H NMR (CDCl3) δ: 8.2-8.14 (m, 1H), 7.9-7.86 (m, 1H), 7.72-7.66 (m, 1H), 7.61-7.55 (m, 1H), 6.50 (s, 1H), 4.05-3.85 (m, 2H), 3.25-3.1 (m, 2H), 3.19 (s, 2H), 1.9-1.7 (m, 5H), 1.47 (s, 9H); LCMS: 404 [M+H].
