[Br-].[Cl:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[CH2:9][P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C([Li])CCC.[CH2:34]1[O:44][C:37]2([CH2:42][CH2:41][C:40](=O)[CH2:39][CH2:38]2)[O:36][CH2:35]1>O1CCCC1>[Cl:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[CH:9]=[C:40]1[CH2:41][CH2:42][C:37]2([O:44][CH2:34][CH2:35][O:36]2)[CH2:38][CH2:39]1A stirred solution of 18.0 grams (0.039 mole) of 2-chlorophenylmethyltriphenylphosphonium bromide in about 50 mL of dry tetrahydrofuran was cooled in a dry ice-acetone bath, and 15.4 mL (0.039 mole) of n-butyllithium (2.5M in hexanes) was added dropwise. Upon completion of addition, the reaction mixture was stirred for 1 hour. After this time a solution of 5.0 grams (0.032 mole) of 1,4-cyclohexanedione mono-ethylene ketal in about 5.0 mL of dry tetrahydrofuran was added dropwise. Upon completion of addition, the reaction mixture was allowed to warm to ambient temperature where it was stirred for about 18 hours. After this time the reaction mixture was concentrated under reduced pressure, yielding about 6.9 grams of 8-(2-chlorophenylmethylene)-1,4-dioxaspiro[4.5]-decane. The NMR spectrum was consistent with the proposed structure.
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