Ethyl 4-iodobenzoate → Ethyl 4-[(2,2,4,4-tetramethyl-thiochroman-6-yl)-ethynyl]benzoate

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A solution of 110.7 mg (0.481 mmol) of 2,2,4,4,-tetramethyl-6-ethynylthiochroman (Compound 3) and 142.3 mg (0.516 mmol) of ethyl 4-iodobenzoate (Compound 97) in 2 ml of triethylamine was placed in a heavy walled glass tube and degassed under argon. The mixture was then treated with a finely ground mixture of 42 mg (0.221 mmol) of cuprous iodide and 63 mg (0.09 mmol) of bis (triphenylphosphine) palladium (II) chloride. The reaction mixture was degassed under argon again and the tube was sealed. The mixture was stirred at room temperature for 40 hours. The triethylamine was removed under vacuum and the residue purified by flash chromatography (silica, 3% ethyl acetate in hexanes) to give the title compound as a pale yellow solid. PMR (CDCl3): δ 1.37-1.42 (15H, m), 1.96 (2H, s), 4.38 (2H, q, J~7.0 Hz), 7.25 (1H, dd, J~8.2 Hz, 1.8 Hz), 7.33 (1H, d, J~1.8 Hz), 7.37 (1H, d, J~8.2 Hz), 7.65 (2H, d, J~8.6 Hz), 8.01 (2H, d, J~8.6 Hz). MS exact mass, m/e 378.1636 (calcd. for C24H26O2S, 378.165.3).

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