[3-(Adamantan-1-yl)-4-(benzyloxy)phenyl]boronic acid → ethyl(E)-3-{2-[3-(1-adamantyl)-4-benzyloxyphenyl]-5-pyrazinyl}-2-propenoate

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(1-adamantyl)-4-benzyloxyphenylboronic acid (474 mg, 1.31 mmol) and ethyl(E)-3-(5-bromo-2-pyrazinyl)-2-propenoate (278 mg, 1.08 mmol) in DME (11 mL, degassed) was added tetrakis(triphenylphosphine)palladium (151 mg, 0.13 mmol) and degassed 2 M Na2CO3 (2.3 mL). The reaction mixture was heated at reflux (90° C. oil-bath) for 19.5 h, cooled to room temperature, and then diluted with EtOAc (155 mL). The organic layer was washed (H2O and brine) and dried. After solvent removal at reduced pressure, the residue was purified on silica gel (10% to 25% EtOAc/hexane) to give 488 mg (91%) of ethyl(E)-3-{2-[3-(1-adamantyl)-4-benzyloxyphenyl]-5-pyrazinyl}-2-propenoate as a yellow solid, mp 145-148° C. IR 2899, 1710, 1238 cm−1; 1H NMR δ (CDCl3) 1.35 (t, J=7.3 Hz, 3H, OCH2CH3), 1.73 (bs, 6H, AdCH2), 2.06 (bs, 3H, AdCH), 2.20 (bs, 6H, AdCH2), 4.29 (q, J=7.3 Hz, 2H, OCH2CH3), 5.19 (s, 2H, CH2), 6.98 (d, J=15.9 Hz, 1H, CH═CHCO), 7.04 (d, J=8.5 Hz, 1H, 5-ArH), 7.28-7.52 (m, 5H, C6H5), 7.72 (d, J=15.9 Hz, 1H, CH═CHCO), 7.84 (dd, J=8.5 Hz, 2.4 Hz, 1H, 6-ArH), 8.02 (d, J=2.4 Hz, 1H, 2-ArH), 8.63 (d, J=1.24 Hz, 1H, 3-PyrH), 8.99 ppm (d, J=1.24 Hz, 1H, 6-PyrH). HRMS calcd C32H34N2O3 [M+H]+ 495.2642. found 495.2659.

Provenance & Evidence