【 Smith K, Hou D., J. Org. Chem. 1996, 61, 1530】
To 4-bromotoluene (518 mg, 3.1 mmol) was added n-BuLi(2.3 M in hexane, 1.35mL, 3 mmol) over 10 min with cooling (ice bath). After 6 hours, the supernatantsolution used in the next stage. To a stirred suspension of crystalline STTAC(sulfur trioxide-trimethylamine complex, commercially available) (431 mg, 3.1mmol) in dry THF (15 mL) at –78 oC was added the preformed hexanesolution of p-tolyllithium dropwise over 15 min. The reaction mixturewas stirred for 2 hours at – 78 oC and then allowed to warm to roomtemperature over 18 hours. After removal of solvent, H2O (10 mL) andKOH (3M, 1 mL, 3 mmol) wereadded to the mixture, which was then extracted with Et2O to removeunreacted 4-bromotoluene. The aqueous solution was evaporated to a white solid.HCl(6 M, 4 mL, 24 mmol) wasadded. The mixture was extracted with EtOAc (4×20 mL), and the combined organicextract was dried (MgSO4) and evaporated to give a moist solid. Et2O(15 mL) was added and some white solid precipitated. This was washed withfurther Et2O (2×10 mL). The combined Et2O extracts wereconcentrated to give white crystals (383 mg, 62%) of the monohydrate.