Boron trifluoride etherate → 5-Allyloxy-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

Participants

Reaction Steps

To a solution of 5-methoxy-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester, 3, (9.86 g, 38.0 mmol) and allyltrimethylsilane (13.0 g, 114 mmol) in CH2Cl2 (200 mL) at −78° C. is added dropwise boron trifluoride etherate (4.82 mL, 38.0 mmol). Once consumption of the starting material is complete, water is cautiously added to quench the reaction. The resulting solution is taken up in ethyl acetate (200 mL) washed with water (1×250 mL), brine (1×250 mL), and dried with Na2SO4. The organics are concentrated in vacuo. The resulting residue is purified over silica (hexanes/ethyl acetate 85:15) to afford 6.2 g (61% yield) of the desired product as a light yellow oil. 1H-NMR (300 MHz, CDCl3): δ 5.85–5.70 (m, 1H), 5.09–5.00 (m, 2H), 4.31–4.16 (m, 1H), 3.95–3.76 (br m, 1H), 3.71–3.69 (m, 3H), 2.72–2.57 (br m, 1H), 2.24–1.69 (m, 5H), 1.45–1.38 (m, 9H); MS (ESI): m/e=270.11 (M+H).

Provenance & Evidence