Synthesis and Comparison of the Reactivity of Allyl Fluorides and ...

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Chapter Six
MeCN (5 cm 3 ) were added to the dropping funnel, the temperature of the flask cooled to 0
°C, and the solution of Selectfluor added dropwise. The mixture was stirred for 3 h at room
temperature. The reaction was quenched by addition of saturated aqueous ammonium
chloride. The mixture was then extracted with DCM, washed with brine, and dried over
anhydrous Na2SO4. The solvent was evaporated and the residue was purified by column
chromatography [hexane: DCM (20:80)] affording the product as a white solid (0.62 g, 58
%). δH 5.64 (1H, d, 2 JHF = 45.8 Hz, CHF), 7.55 (4H, tm, 3 JHH = 7.4 Hz, ArH-3), 7.70 (2H,
tm, 3 JHH = 7.4 Hz, ArH-4), 7.92 (4H, dm, 3 JHH = 7.4 Hz, ArH-2); δC 104.8 (d, JCF = 266.6 Hz,
CHF), 128.5 (ArCH-3), 129.2 (ArCH-2), 134.4 (ArC-1), 134.7 (ArCH-4); δF -168.1 (1F, s,
CHF). m/z (EI + ) 314 ([M] + , 5 %), 141 ([M-C6H5SO2CHF] + , 55 %). HRMS (EI) 314.00814
(C13H11O4FS2 requires 314.00801).
6.4.8 Preparation of Dimethyl 2-(4-(benzoyloxy)but-2-enyl)malonate (151) [19]
The title compound was prepared using a
method outlined by Gouverneur et al. [14] A 50
cm 3 , two-necked round-bottomed flask was
equipped with a magnetic stirring bar, and
Rotaflo tap and attached to a Schlenk line. After flame-drying under high vacuum, the flask
was cooled and filled with nitrogen. [Pd(C3H5)Cl]2 (3 mg, 0.008 mmol) was added to the
reaction flask in a dry box. Subsequently, the flask was reattached to the Schlenk line, filled
with nitrogen and charged with PPh3 (83 mg, 0.32 mmol) and anhydrous DCM (3 cm 3 ) and
stirred at room temperature for 15 minutes. After which, 2-fluorobut-3-enyl benzoate (62
mg, 0.32 mmol), sodium dimethylmalonate (148 mg, 0.96 mmol) and 15-crown-5 (0.19
cm 3 , 0.96 mmol) were added and the reaction mixture left to stir. After stirring overnight,
the reaction was quenched with water (10 cm 3 ) and the aqueous phase extracted with diethyl
ether (3 x 10 cm 3 ). The combined organic phases were dried over MgSO4, concentrated in
vacuo and was purified by column chromatography [hexane: ethyl acetate (70:30)] affording
the product as a colourless oil (45 mg, 46 %). δH 2.62 (2H, dd, 3 JHH = 7.4 Hz, 3 JHH = 5.5 Hz,
Hb), 3.41 (1H, t, 3 JHH = 7.4 Hz, Ha), 3.66 (6H, s, CH3), 4.68 (2H, d, 3 JHH = 4.7 Hz, Hd), 5.74
(2H, m, Hc), 7.40 (2H, tm, 3 JHH = 7.8 Hz, ArH-3), 7.55 (1H, tm, 3 JHH = 7.4 Hz, ArH-2), 8.05
(2H, dm, 3 JHH = 8.2 Hz, ArH-4); δC 31.5 (CH2CH(COOMe)2), 51.3 (CH(COOMe)), 52.6
(CH3), 64.9 (OCH2), 127.4 (CHCH2COOMe), 128.5 (ArCH-3), 130.2 (ArC-1), 130.2
(ArCH-2), 130.8 (OCH2CH), 133.8 (ArCH-4), 166.3 (ArC=O), 169.2 (C=O). m/z (FAB + )
307 ([MH] + , 100 %). HRMS (FAB) 307.11768 C16H19O6 requires 307.11769).