反应详情

A solution of 3.03 g (11 mmol) of the resultant compound of Example 1 in 120 ml of 1:1 dichloromethane:methanol was cooled to 0° C., and treated with 4.10 g (11 mmol) of cerium(III) chloride heptahydrate. The resulting solution was immediately cooled to -78° and treated slowly with a solution of 0.63 g (16.5 mmol) of sodium borohydride in 15 ml of ethanol in such a way that the ethanolic solution was precooled by the side of the flask. After 1 h, the solution was quenched by addition of aqueous ammonium chloride, extracted with ether, washed sequentially with aqueous NaHCO3 and saturated brine, dried over MgSO4 and concentrated in vacuo to give a 4.7:1 ratio of diastereomeric products. Silica gel chromatography of the residue using 3:1 hexane:ethyl acetate provided 1.58 g (52%) of the pure desired compound (Rf 0.35, 15% ethyl acetate in chloroform) as a white solid (m.p. 122°-124° C.), along with 0.22 g (7%) of (3R,4S)-4-(t-butyloxycarbonylamino)-3-hydroxy-5-phenyl-1-pentene. 1H NMR (CDCl3) δ 1.37 (s, 9 H), 2.73 (dd, J=15, 9 Hz 1 H), 2.85 (dd J=15, 5 Hz, 1 H), 2.98 (m, 1 H), 3.98 (m, 1 H), 4.24 (m, 1 H), 4.58 (br, 1 H), 5.29 (dt, J=10, 1.5 Hz, 1 H), 5.38 (dt, J=17, 1.5 Hz, 1 H), 5.94 (ddd, J=17, 10, 6 Hz, 1 H), 7.2-7.3 (m, 5 H).

1. temperatureThe resulting solution was immediately cooled to -78°
2. customthe solution was quenched by addition of aqueous ammonium chloride
3. extractionextracted with ether
4. washwashed sequentially with aqueous NaHCO3 and saturated brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated in vacuo
7. customto give a 4.7:1 ratio of diastereomeric products