Under nitrogen, 36.4 g (161 mmol) of 1,2-dibromocyclopentene (Aldrich) was reacted with 18.0 g (107 mmol) of 4-methylthiophenylboronic acid (Step 1) in 550 mL of toluene, 365 mL of ethanol, and 235 mL of 2M Na2CO3 in the presence of 6.0 g (5 mol %) of Pd(PPh3)4. The reaction was vigorously stirred at reflux overnight and concentrated in vacuo. The residue was dissolved in ethyl acetate and washed with water, dried (MgSO4), and reconcentrated. Purification by silica gel chromatography (Waters Prep-500) with hexane gave 9.39 g (22%) of 1-(2-bromocyclopenten-1-yl)-4-(methylthio)benzene (38 in Synthetic Scheme X when R5 =SCH3 and R1, R2, R3, R4, R6, and R7 =H) as a solid: mp 52°-54° C.; NMR (CDCl3) d 1.98-2.09 (m, 2H), 2.50 (s, 3H), 2.70-2.78 (m, 2H), 2.80-2.89 (m, 2H), 7.24 (d, J=8 Hz, 2H), 7.55 (d, J=8 Hz, 2H).
