反应详情

A solution of tert-butyl 3-formyl-3,4-dihydroisoquinoline-2(1H)-carboxylate (8.4 g, 32.2 mmol) in dry THF (200 mL, 0.16 M) was treated with (ethoxycarbonylmethylene)triphenylphosphorane (12.8 g, 37.0 mmol) in one portion. After stirring at room temperature overnight, the solvent was evaporated, and the resulting residue was dissolved in ether. Heptane was added and the precipitated triphenylphosphine oxide was filtered off. The filtrate was concentrated and purified by flash chromatography (5-20% ethyl acetate in hexane) affording (E)-tert-butyl 3-(3-ethoxy-3-oxoprop-1-enyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate as yellow oil (8.7 g, 82%). 1H NMR (CDCl3, 500 MHz) δ 7.21-7.14 (m, 2H), 7.14-7.07 (m, 2H), 6.74 (dd, J1=15.8 Hz, J2=4.8 Hz, 1H), 5.79 (dd, J1=15.8 Hz, J2=1.3 Hz, 1H), 4.72 (d, J=16.5 Hz, 1H), 4.35 (d, J=16.5 Hz, 1H), 4.11 (qw, J=14.4 Hz, 2H), 3.18 (dd, J1=15.8 Hz, J2=6.2 Hz 1H), 2.84 (d, J=15.8 Hz, 1H), 1.49 (s, 9H), 1.23 (t, J=14.4 Hz, 3H). ESI MS found for C19H25NO4 m/z [354.4 (M+23)].

1. customthe solvent was evaporated
2. dissolutionthe resulting residue was dissolved in ether
3. additionHeptane was added
4. filtrationthe precipitated triphenylphosphine oxide was filtered off
5. concentrationThe filtrate was concentrated
6. custompurified by flash chromatography (5-20% ethyl acetate in hexane)