[CH2:1]1[C:5]2([CH2:10][CH2:9][CH2:8][CH2:7][C:6]2=[O:11])[CH2:4][CH2:3][CH2:2]1.[C:12]1(=O)CCCC[CH2:13]1.BrCCCCBr.[NH4+].[Cl-].Cl>C1COCC1.C1(C)C=CC=CC=1>[C:12]([C:6]1([OH:11])[CH2:7][CH2:8][CH2:9][CH2:10][C:5]21[CH2:1][CH2:2][CH2:3][CH2:4]2)#[CH:13]At 5° C., a solution of lithium acetylide ethylene diamine complex (200 g, 2.17 mol) in THF (1 l) was treated dropwise with a solution of spiro[4.5]decan-6-one (196 g, 1.29 mol, prepared from cyclohexanone and 1,4-dibromobutane in the presence of potassium tert.-butylate in toluene) in THF (0.8 l). The resulting mixture was stirred for 3 h at 20° C., poured into a saturated aqueous solution of NH4Cl, acidified with conc. HCl and extracted three time with MTBE (500 ml). The aqueous phase was extracted twice with MTBE (150 ml) and the combined organic phases were washed twice with water (500 ml), once with a saturated aqueous solution of NaCl, dried (MgSO4), and concentrated. Short-path Vigreux-distillation (0.08 mbar, bath temperature: 140° C., head temp.: 100-105° C.) of the crude product (257 g) gave 6-ethynylspiro[4.5]decan-6-ol (180.8 g, 79%).
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