[CH3:1][O:2][CH:3]([C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1Br.C([Li])CCC.[O:22]1[C:26]2([CH2:31][CH2:30][C:29](=O)[CH2:28][CH2:27]2)[O:25]C[CH2:23]1>O1CCCC1.CCCCCC.O>[C:4]1([CH:3]2[C:11]3[C:16](=[CH:15][CH:14]=[CH:13][CH:12]=3)[C:1]3([CH2:23][O:22][C:26]4([CH2:31][CH2:30][CH2:29][CH2:28][CH2:27]4)[O:25]3)[O:2]2)[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1
To a cooled (-50° C.) stirred solution of 27.7 g of 2-bromobenzhydryl methyl ether in 80 ml of dry tetrahydrofuran is added dropwise under nitrogen 60 ml of 2.4 M n-butyllithium in hexane. The mixture is stirred for 2 hours and a solution of 15.9 g of 1,4-dioxaspiro[4.5]decan-8-one in 50 ml of dry tetrahydrofuran is added dropwise, maintaining the temperature at -40° to -30° C. The mixture is stirred overnight at -70° to +10° C., diluted with 100 ml of water and extracted with 100 ml of dichloromethane. The organic phase is washed with water (2×50 ml), dried over anhydrous sodium sulfate and concentrated in vacuo. A solution of the residue in 400 ml of ethanol is stirred with 50 ml of hydrogen bromide/ether at room temperature for 3 hours. The solvent is removed under reduced pressure and the remaining oil crystallizes from 100 ml of methanol to give 39.6% of product, mp 130°-132° C.
読み込み中…
