反应详情

The Grignard reagent is prepared from 3.70 ml of 4-bromo-1-butene and 880 mg of magnesium powder in 50 ml of tetrahydrofuran at 55° C. This solution is then added dropwise to a solution of 3.0 g of 2(S)-tert-butoxycarbonylamino-6-triisopropylsilyloxy-4,4-dimethyl-hexanal (Example 1g)) in 25 ml of tetrahydrofuran at 5°-10° C. 1 h after the end of the addition, the mixture is poured onto a 0.1N hydrochloric acid solution, extracted with methylene chloride and concentrated. The crude product contains the two 5(S):5(R) diastereomers in a ratio of about 5:1. The title compound (non-polar diastereomer) is obtained by purification over 250 g of silica gel (mobile phase E): Rf (E)=0.30.

1. addition1 h after the end of the addition
2. extractionextracted with methylene chloride
3. concentrationconcentrated