Ethyl propiolate → HCID 67111289, compound

Participants

Reaction Steps

A mixture of ethyl propiolate (0.85 mL, 8.36 mmol) in THF (20 mL) was treated with a 2.5 M solution of n-BuLi in THF (3.3 mL, 8.3 mmol) at −78° C., stirred for 10 min, followed by addition of a 1.0 M solution of zinc chloride in THF (8.4 mL, 8.4 mmol). Warmed reaction to RT, added a solution of N-Boc-2-amino-5-iodo-2,3-dihydro-1H-indene (0.800 g, 2.22 mmol) in THF (1 mL) followed by Pd(PPh3)4 (0.30 g, 0.26 mmol). Warmed reaction mixture to 60° C., stirred for 2 hours, then cooled. Diluted with DCM, washed with 1 N HCl, water, dried (Na2SO4), conc. Chromatography on SiO2 (0-50% EtOAc/hexanes) gave the intermediate ethyl 3-{2-[(tert-butoxycarbonyl)amino]-2,3-dihydro-1H-inden-5-yl}prop-2-ynoate (392 mg, 54% yield): 1H NMR (600 MHz, CDCl3) δ 7.41 (s, 1H), 7.39 (d, J=8.5 Hz, 1H), 7.19 (d, J=7.6 Hz, 1H), 4.71 (br s, 1H), 4.45 (br s, 1H), 4.27 (q, J=7.0 Hz, 2H), 3.23-3.28 (m, 2H), 2.75-2.81 (m, 2H), 1.42 (s, 9H), 1.33 (t, J=Hz, 3H); MS cal'd for C19H23NO4Na [M+Na]+352.2. found 352.1.

Provenance & Evidence