Sodium Iodide → 4-trimethylsilanyloxy-7,8-dihydro-6H-cyclohepta[b]pyrrole-1,3-dicarboxylic acid 1-tert-butyl ester 3-ethyl ester

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Reaction Steps

To a solution of 4-oxo-5,6,7,8-tetrahydro-4H-cyclohepta[b]pyrrole-1,3-dicarboxylic acid 1-tert-butyl ester 3-ethyl ester (2.17 g, 6.72 mmol), NaI (1.51 g, 10.07 mmol) and triethylamine (2.80 mL, 20.14 mmol) in CH3CN (30 mL), is added trimethylsilyl chloride (1.27 mL, 10.07 mmol) slowly via syringe. The reaction mixture is stirred at room temperature for 20 h. and then partitioned between 50 mL of ethyl acetate/hexanes (1:1 with a few drops of triethylamine) and 30 mL of sat. NaHCO3 solution. The layers are separated and the aqueous phase is extracted with ethyl acetate/hexanes (1:1) (3×20 mL). The combined organic layers are washed with brine, dried (Na2SO4) and evaporated to provide 4-trimethylsilanyloxy-7,8-dihydro-6H-cyclohepta[b]pyrrole-1,3-dicarboxylic acid 1-tert-butyl ester 3-ethyl ester (2.56 g, 100%) as viscous red oil. 1H NMR (400 MHz, CDCl3) δ 0.177 (9H, s), 1.308 (3H, t), 1.585 (9H, s), 1.906 (2H, m), 2.016 (2H, m), 2.974 (2H, t), 4.243 (2H, q), 5.353 (1H, t), 7.627 (1H, s). MS (ES+) 395 (M+1). Step 3:

Provenance & Evidence