Di-tert-butyl Dicarbonate [Boc-reagent for Amino Acid]

Used Chemicals

• Indole [I0021]
• Di-tert-butyl Dicarbonate (= Boc₂O) [D1547]
• 4-Dimethylaminopyridine (= DMAP) [D1450]
• THF

Procedure

To a solution of indole (200 mg, 1.71 mmol) in THF (2 mL) was added DMAP (21 mg, 0.17 mmol, 0.1 eq.) and Boc₂O (467 mg, 2.13 mmol, 1.25 eq.) at r.t. and stirred overnight. The reaction mixture was diluted with ethyl acetate (20 mL) and washed with water (15 mL) and brine (15 mL). Then the organic layer was dried over sodium sulfate and filtered. The solvent was removed under reduced pressure to give N-Boc-indole as a colorless liquid (392 mg, >99% yield).

Experimenter’s Comments

Gas was generated during the reaction.

Analytical Data

N-Boc-indole

¹H NMR (270 MHz, CDCl₃); δ 8.14 (d, 1H, J = 8.1 Hz), 7.59 (t, 1H, J = 4.1 Hz), 7.57 (d, 1H, J = 7.7 Hz), 7.32 (dt, 1H, J = 6.8, 1.4 Hz), 7.23 (dt, 1H, J = 7.7, 0.8 Hz), 6.58 (d, 1H, J = 4.1 Hz), 1.68 (s, 9H).

Lead Reference/

• Visible light-induced 3-sulfenylation of N-methylindoles with arylsulfonyl chlorides
• M. Chen, Z. Huang, Q. Zheng, Chem. Commun. 2012, 48, 11686.

References

• V. Perron, S. Abbott, N. Moreau, D. Lee, C. Penney, B. Zacharie, Synthesis 2009, 283.