Tricyclohexylphosphine → 3-benzenesulfonyl-3H-indene-1-carboxylic acid ethyl ester

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A solution of tricyclohexylphophine (46 mg, 0.164 mmol) in tetrahydrofuran (2.5 mL) under nitrogen was charged with palladium (II) acetate (24.5mg, 0.109 mmol). The reaction mixture was stirred for 45 minutes, then cooled to 0° C. and charged with sodium tert-butoxide (270 mg, 2.73 mmol). After 5 minutes a solution of β-ethoxyacrylic acid ethyl ester (158 μL, 1.09 mmol) and 2-bromobenzyl phenyl sulfone (340 mg, 1.09 mmol) in tetrahydrofuran (2.5 mL) was added dropwise over 2 minutes. Upon complete addition the reaction was warmed to room temperature and then heated to 60° C. for 2 hours. The reaction was cooled to room temperature, then diluted with methyl tert-butyl ether (25 mL) and poured into aqueous potassium dihydrogen phosphate (0.25 M, 25 mL), pH=7. The aqueous layer was separated and saturated by addition of solid sodium chloride and extracted with ethyl acetate (2×50 mL). The organic layer was separated and washed twice with aqueous saturated sodium chloride (2×30 mL), dried over sodium sulfate, filtered and concentrated in vacuo affording 3-benzenesulfonyl-3H-indene-1-carboxylic acid ethyl ester as a light orange oil (304 mg, 0.925 mmol, 85%). 1H NMR (400 MHz, CDCl3) δ 7.88–7.86 (m, 1H), 7.75–7.72 (m, 1H), 7.49–7.43 (m, 3H), 7.36–7.32 (m, 2H), 7.27–7.25 (m, 3H), 5.15 (d, 1H, J=2.1), 4.27 (q, 2H, J=7.1), 1.34 (t, 3H, J=7.1); IR (ATR, neat) 1709, 1649, 1463, 1444, 1314, 1271, 1247, 1188, 1133, 1081, 1044, 773, 752, 722, 686, 575, 528.

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