[CH3:1][O:2][CH:3]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.CC(C)([O-])C.[K+].[C:29]12([O:44][CH2:43][CH2:42][O:41]1)[C:38]1[C:33](=[CH:34][CH:35]=[CH:36][CH:37]=1)[CH2:32][C@@H:31]([CH:39]=O)[CH2:30]2>O1CCCC1>[CH3:1][O:2][CH:3]=[CH:39][C@@H:31]1[CH2:32][C:33]2[C:38](=[CH:37][CH:36]=[CH:35][CH:34]=2)[C:29]2([O:44][CH2:43][CH2:42][O:41]2)[CH2:30]1To a stirred solution of (methoxymethylene)triphenylphosphorane (6.74 g, 21.99 mmol) in tetrahydrofuran (30 mL) was added drop-wise a solution of potassium tert-butoxide (3.08 g, 27.5 mmol) in THF at −30° C. under argon, and the mixture was stirred for 30 min. Then a solution of (R)-3′,4′-dihydro-2′H-spiro[[1,3]dioxolane-2,1′-naphthalene]-3′-carbaldehyde (4.0 g, 18.33 mmol) in THF was added drop-wise and reaction was stirred for 1 h at −30° C. Reaction was monitored by TLC. Reaction mixture quenched with water at −30° C. and allowed to RT, diluted with water (25 mL) and extracted with ethyl acetate (2×50 mL), dried over Na2SO4, filtered and concentrated to give crude product (8 g). The crude compound was purified with silica gel flash column chromatography (Biotage) to give (R)-3′-(2-methoxyvinyl)-3′,4′-dihydro-2′H-spiro[[1,3]dioxolane-2,1′-naphthalene] (3.5 g, 14.21 mmol, 78% yield) as colourless liquid; m/z 246.6.
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