Diisopropylethylamine → methyl 4-ethyl-2-formyl-5-[3-(trimethylsilyl)prop-1-ynyl]-1H-pyrrole-3-carboxylate

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Reaction Conditions

Reaction Steps

Methyl 4-ethyl-2-formyl-5-iodo-1H-pyrrole-3-carboxylate was obtained following the procedures described in Example 3. Pd(Pt-Bu3)4 (18.4 mg, 0.040 mmol), Pd2(dba)3 (16.5 mg, 0.020 mmol), and CuI (4.6 mg, 0.020 mmol) were combined in a dry flask under N2 prior to evacuating the flask and refilling with argon. After the flask was charged with dioxane (4.0 mL), i-Pr2NEt (0.0675 mL, 0.48 mmol), trimethyl(prop-2-ynyl)silane (90.0 mg, 0.80 mmol), and methyl 4-ethyl-2-formyl-5-iodo-1H-pyrrole-3-carboxylate (123.0 mg, 0.40 mmol) were added sequentially. The reaction was stirred overnight at 80° C. After the reaction was cooled to ambient temperature, it was filtered through a plug of silica gel and concentrated in vacuo. The resultant residue was dissolved in acetonitrile and purified by reverse phase HPLC. Proton NMR for the product was consistent with the title compound. 1H NMR (500 MHz, CDCl3) δ 10.04 (s, 1H); 3.90 (s, 3H); 2.78 (q, J=7.5 Hz, 2H); 1.77 (s, 2H); 1.16 (t, J=7.5 Hz, 3H); 0.17 (s, 9H). HRMS (ES) exact mass calculated C15H22NO3Si (M+H): 292.1364. Found 292.1364

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