Reaction Steps
A solution of tert-butyl((3S,7R,8R,9S)-8-hydroxy-7-(4-methoxybenzyl)-9-methyl-2-oxooxonan-3-yl)(methoxymethyl)carbamate (350 mg, 0.775 mmol), palladium tetrakis(triphenylphosphine) (90 mg, 0.078 mmol), and allyl tert-butyl carbonate (758 mg, 4.79 mmol) in degassed THF (3876 μl) was heated to 60° C. and stirred for 4 h. The reaction mixture was cooled to room temperature and purified directly by column chromatography on SiO2 (EtOAc/Hex gradient) to afford the title product as a light yellow oil (200 mg, 52.5%): IR (neat) 2977, 2934, 2836, 1746, 1702, 1511, 1367, 1297, 1246, 1175 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.07 (d, J=8.5 Hz, 2H), 6.81 (d, J=8.6 Hz, 2H), 6.02-5.88 (m, 1H), 5.33 (dd, J=17.2, 1.6 Hz, 1H), 5.20 (dd, J=10.4, 1.5 Hz, 1H), 4.94-4.81 (m, 2H), 4.76 (t, J=10.3 Hz, 1H), 4.60-4.50 (m, 1H), 4.28 (dd, J=11.8, 5.6 Hz, 1H), 4.22-4.15 (m, 1H), 4.09 (dd, J=11.9, 5.3 Hz, 1H), 3.78 (s, 3H), 3.30 (d, J=14.5 Hz, 3H), 3.21 (t, J=9.0 Hz, 1H), 3.03 (dd, J=13.5, 3.4 Hz, 1H), 2.34-2.22 (m, 1H), 2.15-1.98 (m, 1H), 1.80 (s, 1H), 1.65-1.59 (m, 2H), 1.50-1.39 (m, 13H), 0.90-0.76 (m, 1H); 13C NMR (101 MHz, CDCl3) δ 173.53, 157.82, 134.40, 134.36, 132.63, 129.69, 117.12, 113.73, 84.28, 84.24, 81.09, 74.62, 58.57, 57.06, 55.24, 55.22, 46.01, 35.97, 28.32, 28.23, 26.57, 19.22, 18.26; HRMS-ESI (m/z) ([M]+) calcd for C27H41NO7, 491.2883; found, 491.2862.
