Triacetoxyperiodinane → (3aS,6S,6aS)-(9H-Fluoren-9-yl)methyl 6-(methylthio)-3-oxotetrahydro-2H-furo[3,2-b]pyrrole-4(5H)-carboxylate

Participants

Reaction Steps

Dess-Martin periodinane (130 mg, 0.65 mmol) was added to a stirred solution of alcohol (55) (278 mg, 0.33 mmol) in dichloromethane (10 mL) under an atmosphere of argon. The mixture was stirred for 1 hour then diluted with dichloromethane (25 mL). The organic phase was washed with a mixture of saturated aqueous sodium bicarbonate and 10% aqueous sodium thiosulphate solution (1:1, 20 mL), then dried (Na2SO4), filtered and reduced in vacuo. Flash chromatography over silica, eluting with diethyl ether:pentane mixtures 60:40 to 65:35 gave ketone (56) (113 mg, 87%) as a white solid. TLC (Rf=0.24, Et2O:pentane 2:1); analytical HPLC two main peaks, Rt=15.71 and 15.91 min.; HPLC-MS 396.1 [M+H]+, 414.1 [M+H2O+Na]+, 813.2 [2M+H]+; [α]D18−137.3° (c=2.33, CHCl3). δH(500 MHz, CDCl3) mixture of rotamers approx. 1:1; 2.15 (1.5H, s, SCH3), 2.19 (1.5H, s, SCH3), 3.30-3.38 (1H, m, CHSMe), 3.68-3.80 (1.5H, m, FmocNCH2), 3.93-4.05 (1.5H, m, 0.5×FmocNCH2 and OCH2C═O), 4.10-4.35 (2.5H, m, OCH2C═O, Fmoc-CH, and 0.5×Fmoc-CH2), 4.40-4.54 (2.5H, m 1.5×Fmoc-CH2 and FmocNCH), 4.74-4.84 (1H, m, OCHCHSCH3), 7.28-7.77 (8H, Fmoc aromatic CH); δC (125 MHz, CDCl3); 14.662 (SCH3), 47.133 (Fmoc-CH), 48.449/48.954 (CHSCH3), 50.539/53.419 (FmocNCH2), 61.005/61.420 (FmocNCH), 67.710/68.437 (Fmoc-CH2), 70.733 (OCH2C═O), 85.174/86.042 (OCHCHSCH3), 119.916, 119.987, 124.917, 124.964, 125.240, 125.448, 127.069, 127.712 and 127.969 (Fmoc aromatic CH), 141.255/141.317, 143.627, 143.778 and 144.264 (Fmoc quaternary), 154.942/155.049 (Fmoc C═O), 207.818/207.973 (ketone C═O).

Provenance & Evidence