反应详情

A catalytic amount of tetrakis(triphenylphosphine)palladium (12.0 mg, 10.4 μmol) was added to a stirred solution of the Alloc-protected carbinolamine 20 (0.18 g, 0.40 mmol), triphenylphosphine (5.25 mg, 20 μmol) and pyrrolidine (29 mg, 0.41 mmol) in CH2Cl2 (15 mL). After 2 hours stirring at room temperature under a nitrogen atmosphere, TLC (98% CHCl3/MeOH) revealed the complete consumption of starting material. The solvent was evaporated in vacuo and the crude residue was purified by flash chromatography (60% EtOAc/Petroleum Ether) to afford 21 (SJG-244) as a white glass (116 mg, 83%) which was repeatedly evaporated in vacuo with CHCl3 in an attempt to provide the N10-C11 imine form: [α]22D=+754.2° (c=0.54, CHCl3); 1H NMR (270 MHz, CDCl3) (mainly imine, plus trace of carbinolamine form) δ 7.70-7.30 (m, 7H, HCαN and 6Harom), 6.84 (s, 1Harom), 5.25-5.13 (m, 4H, NCH2C═CH2 and PhCH2O), 4.42 (br s, 2H, NCH2C═CH2), 3.95 (s, 3H, OCH3), 3.88-3.66 (m, 1H, NCHHC═N), 3.09 (dd, 1H, J=8.98, 16.12 Hz, NCH2C═CH2CH2), 2.94-2.87 (m, 1H, NCH2C═CH2CH2); 13C NMR (67.8 MHz, CDCl3) δ 164.7 (NC═O), 162.6 (HC═N), 150.6 (Cquat), 148.1 (Cquat), 141.6 (Cquat), 140.5 (Cquat), 136.1 (Cquat), 132.0, 128.7, 128.6, 128.1 and 127.3 (BnC—Harom), 120.1 (Cquat), 111.5 (C—Harom), 111.2 (C—Harom), 109.4 (NCH2C═CH2), 70.8 (PhCH2O), 56.2 (OCH3), 53.7 (NCHHC═N), 51.3 (NCH2C═CH2), 35.4 (NCH2C═CH2CH2); MS (EI), m/z (relative intensity) (imine form) 348 (M+, 100), 333 (M-CH3, 42), 319 (3), 269 (5), 257 (M-PhCH2, 25), 241 (11), 229 (56), 227 (11), 213 (5), 186 (4), 156 (6), 136 (22), 122 (4), 91 (PhCH2, 85), 82 (5), 65 (22); IR (NUJOL7) 3318 (br, OH of carbinolamine form), 2923, 2853, 1722, 1668, 1600, 1557, 1504, 1462, 1377, 1261, 1216, 1120, 1003, 892, 789, 722, 695, 623, 542 cm−1; exact mass calcd for C21H20N2O3m/e 348.1474, obsd m/e 348.1469.

1. customwas repeatedly evaporated in vacuo with CHCl3 in an attempt
2. customto provide the N10-C11 imine form