[1,2-Bis(ethoxycarbonyl)hydrazineyl]triphenylphosphonium Trifluoromethanesulfonate

• Benzyl (S)-(-)-Lactate [L0161]
• Indoline [I0033]
• BEHT Triflate [B7082]
• N,N-Diisopropylethylamine (= DIEA) [D1599]
• 1,2-Dichloroethane (= DCE)

DIEA (0.17 mL, 1.00 mmol) was added to a suspension of benzyl (S)-(-)-lactate (180 mg, 1.00 mmol), indoline (119 mg, 1.20 mmol) and BEHT triflate (704 mg, 1.20 mmol, 1.2 eq.) in DCE (1 mL) at rt and the mixture was stirred at room temperature for one day. The reaction mixture was quenched with sat. NaHCO₃ aq. (5 mL) and the aqueous layer was extracted with dichloromethane (3 x 5 mL). The combined organic layer was washed with brine, dried over sodium sulfate and filtered. The solvent was removed under reduced pressure and the residue was purified by column chromatography (ethyl acetate:hexane = 0:100 – 5:95 on silica gel) to give benzyl (R)-2-(indolin-1-yl)propanoate as a pale red oil (154 mg, 54% yield).

The reaction mixture was monitored by UPLC.

Benzyl (R)-2-(Indolin-1-yl)propanoate

¹H NMR (400 MHz, CDCl₃); δ 7.30-7.26 (m, 3H), 7.18 (dd, J = 3.2, 7.2 Hz, 2H), 7.05 (d, J = 7.3 Hz, 1H), 7.00 (t, J = 7.3 Hz, 1H), 6.64 (t, J = 7.3 Hz, 1H), 6.39 (d, J = 7.3 Hz, 1H), 5.11 (d, J = 12.8 Hz, 1H), 5.07 (d, J = 12.8 Hz, 1H), 4.32 (q, J = 7.0 Hz, 1H), 3.53 (t, J = 8.4 Hz, 2H), 2.95 (t, J = 8.4 Hz, 2H), 1.49 (d, J = 7.0 Hz, 3H).

• Universal Reagent for Mild and Stereospecific Nucleophilic Substitution of Alcohols with Amines
  • W. S. Bechara, I. K. Sagamanova, L. Thai-Savard, M. Dauphinais, S. Régnier, C. Noël, S. B. D. Jarvis, A. B. Charette, Angew. Chem. Int. Ed. 2025, 64, e202420312.