[CH:1]([Li])([CH2:3][CH3:4])C.C([O:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1Br)(=O)C(C)C.[C:19](OCC)(=[O:21])C.C(=O)(O)O.[Na]>C1CCCCC1.O1CCCC1>[OH:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1[C:19](=[O:21])[CH:3]([CH3:1])[CH3:4]100 ml of sec-butyllithium at 1.4 M in cyclohexane were added dropwise to a solution of 31.59 g (130 mmol) of 2-bromophenyl isobutyrate in 300 ml of tetrahydrofuran at −85° C. under nitrogen. The reaction medium was maintained for 30 minutes at approximately −75° C. and was then left to gently return to ambient temperature. After 2 hours, a little ethyl acetate was added, followed by approximately 400 ml of a 1 M aqueous sodium dihydrogen carbonate solution. The organic phase was recovered, washed with water, dried over anhydrous magnesium sulfate, filtered and concentrated. 23.97 g of an orange oil were obtained and purified on silica cake. The residue obtained was chromatographed on a prepacked silica column (eluent heptane/ethyl acetate). 4.3 g of product were obtained in the form of a yellow oil. Yield=20%.
読み込み中…
