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

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Chapter Six
(1H, td, 3 JHH = 8.2 Hz, 4 JHF = 5.9 Hz, ArH-5), 7.67 (1H, ddd, 3 JHF = 9.4 Hz, 4 JHH = 2.7 Hz,
4 JHH = 1.6 Hz, ArH-2), 7.79 (1H, dt, 3 JHH = 7.4 Hz, 4 JHH = 1.6 Hz, ArH-6); δC 64.9 (OCH2),
115.5 (d, 2 JCF = 23.1 Hz, ArCH-2), 117.5 (CHCH2), 119.0 (d, 2 JCF = 21.1 Hz, ArCH-4),
124.4 (ArCH-6), 129.0 (d, 3 JCF = 8.0 Hz, ArCH-5), 130.9 (CHCH2), 131.4 (d, 3 JCF = 7.0 Hz,
ArC-1), 161.6 (d, 1 JCF = 247.5 Hz, ArCF), 164.1 (d, 4 JCF = 3.0 Hz, C=O); δF -112.4 (1F, s,
CF). m/z (EI + ) 180 ([M] + , 70 %), 123 ([M-OCH2CH=CH2] + , 100 %). HRMS (EI)
180.05842 (C10H9O2F requires 180.05843).
6.2.6 Preparation of allyl 2-fluorobenzoate (83) [5]
The title compound was prepared following the method
outlined by Yasui et al. without modification. [2] A 50 cm 3 ,
two-necked round-bottom 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. The flask was charged with 2-fluorobenzoyl chloride (1 g, 0.75 cm 3 , 6.31 mmol)
and anhydrous diethyl ether (7 cm 3 ). The reaction mixture was cooled to 0 °C using an ice
bath. Allyl alcohol (0.33 g, 0.39 cm 3 , 5.73 mmol) and triethylamine (0.64 g, 0.88 cm 3 , 6.31
mmol) were added and the reaction mixture then stirred at 0 ºC for 2 h, after which it was
warmed to room temperature and stirred overnight. The reaction mixture was diluted with
ethyl acetate and the organic layer extracted and washed successively with 2M HCl (2 x 2
cm 3 ), saturated NaHCO3 and brine. The organic layer was dried over MgSO4 and solvent
removed in vacuo to yield the product as a colourless oil (1.01 g, 98 %). δH 4.78 (2H, ap.dt,
3 JHH = 5.5 Hz, 4 JHH = 1.6 Hz, OCH2), 5.23 (1H, ddt, 3 JHH = 10.6 Hz, 2 JHH = 1.2 Hz, 4 JHH =
1.6 Hz, Ha), 5.37 (1H, ddt, 3 JHH = 17.2 Hz, 2 JHH = 1.6 Hz, 4 JHH = 1.6 Hz, Hb), 5.97 (1H, ddt,
3 JHH = 17.2 Hz, 3 JHH = 10.6 Hz, 3 JHH = 5.5 Hz, Hc), 7.07 (1H, ddd, 3 JHF = 11.0 Hz, 3 JHH = 8.2
Hz, 4 JHH = 1.2 Hz, ArH-3), 7.14 (1H, td, 3 JHH = 7.8 Hz, 4 JHH = 1.2 Hz, ArH-5), 7.45 (1H,
dddd, 3 JHH = 8.2 Hz, 3 JHH = 7.4 Hz, 4 JHF = 4.7 Hz, 4 JHH = 2.0 Hz, ArH-4), 7.89 (1H, td, 3 JHH
= 4 JHF = 7.4 Hz, 4 JHH = 2.0 Hz, ArH-6); δC 65.8 (OCH2), 117.0 (d, 2 JCF = 22.1 Hz, ArCH-3),
118.4 (CHCH2), 118.7 (d, 2 JCF = 10.1 Hz, ArC-1), 123.9 (d, 4 JCF = 6.0 Hz, ArCH-5), 131.9
(ArCH-6), 132.1 (CHCH2), 134.5 (d, 3 JCF = 9.1 Hz, ArCH-4), 162.0 (d, 1 JCF = 260.6 Hz,
ArCF), 164.1 (d, 3 JCF = 3.0 Hz, C=O); δF -109.8 (1F, s, CF). m/z (EI + ) 180 ([M] + , 55 %),
123 ([M-OCH2CH=CH2] + , 100 %). HRMS (EI) 180.05838 (C10H9O2F requires 180.05843).