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

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Chapter Six
1 JCF = 253.5 Hz, ArCF); δF –105.2 (1F, s, CF). m/z (EI + ) 210 ([M] + , 4 %) 123 ([M-
OCH2CHOHCH=CH2] + , 100 %). HRMS (EI) 210.06895 (C11H11O3F requires 210.06895).
6.2.31 Preparation of 2-hydroxybut-3-enyl 3-fluorobenzoate (102)
The novel compound was prepared following the
method outlined by Ziegler et al. [10] A 100 cm 3 , three-
necked round-bottom flask was equipped with a
magnetic stirring bar, pressure equalising dropping
funnel and Rotaflo tap and attached to a Schlenk line.
After flame-drying under high vacuum, the flask was cooled and filled with nitrogen. The
funnel was charged with 3-fluorobenzoyl chloride (2.33 g, 1.79 cm 3 , 14.69 mmol) and
pyridine (1.3 cm 3 ). The reaction flask was charged with (±)3-butene-1,2-diol (1.05 g, 1 cm 3 ,
11.88 mmol) and pyridine (5 cm 3 ). The reaction flask was cooled to -35 ºC (isopropanol:
dry ice mixture). The 3-fluorobenzoyl chloride solution was then dropped into the cooled
reaction flask, and the reaction mixture was stirred for 17 h. After which the reaction
mixture was poured into water and extracted with DCM. The extracts were then washed
with 2M HCl and NaHCO3 solution, after which it was dried over Na2SO4, and concentrated
in vacuo. Purification by chromatography [chloroform: hexane (80:20)] afforded the
product as a white solid (1.05 g, 42 %). δH 2.08-2.11 (1H, bs, OH), 4.23 (1H, dd, 2 JHH = 11.3
Hz, 3 JHH = 7.0 Hz, Hd), 4.36 (1H, dd, 2 JHH = 11.3 Hz, 3 JHH = 3.5 Hz, He), 4.44-4.50 (1H, m,
CHOH), 5.23 (1H, ap.dt, 3 JHH = 10.6 Hz, 2 JHH = 4 JHH = 1.6 Hz, Hb), 5.38 (1H, ap.dt, 3 JHH =
17.2 Hz, 2 JHH = 4 JHH = 1.6 Hz, Ha), 5.88 (1H, ddd, 3 JHH = 17.2 Hz, 3 JHH = 10.6 Hz, 3 JHH =
5.9 Hz, Hc), 7.21 (1H, ap.tdd, 3 JHH = 3 JHF = 8.2 Hz, 4 JHH = 2.7 Hz, 4 JHH = 1.2 Hz, ArH-4),
7.36 (1H, td, 3 JHH = 8.2 Hz, 4 JHF = 5.5 Hz, ArH-5), 7.66 (1H, ddd, 3 JHF = 9.4 Hz, 4 JHH = 2.7
Hz, 4 JHH = 1.6 Hz, ArH-2), 7.77 (1H, dt, 3 JHH = 7.8 Hz, 4 JHH = 1.6 Hz, ArH-6); δC 68.5
(OCH2), 71.1 (CHOH), 116.6 (d, 2 JCF = 24.1 Hz, ArCH-2), 117.4 (CHCH2), 120.3 (d, 2 JCF =
19.1 Hz, ArCH-4), 125.4 (ArC-6), 130.1 (d, 3 JCF = 7.0 Hz, ArCH-5), 132.0 (d, 3 JCF = 7.0 Hz,
ArC-1), 136.1 (CHCH2), 162.5 (d, 1 JCF = 246.5 Hz, ArCF), 165.5 (C=O); δF –112.2 (1F, s,
CF). m/z (EI + ) 210 ([M] + , 8 %) 123 ([M-OCH2CHOHCH=CH2] + , 100 %). HRMS (EI)
210.06900 (C11H11O3F requires 210.06895).