My PhD dissertation - Institut Fresnel

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extracted with ethyl acetate (2 × 25 mL) and the combined organic layers were dried with
sodium sulfate and evaporated. The white solid obtained was recrystallized from ethanol to
afford colorless prisms; m.p. 116 - 118 °C; yield: 7.54 g (92%).
1 H NMR: δ = 7.26 (dd, J = 8.0, 1.0 Hz, 2 H), 7.20 (t, J = 8.0 Hz, 2 H), 6.90 (dd,
J = 8.0, 0.8 Hz, 2 H), 4.00 (symm. m, 4 H), 1.21 (t, J = 7.0 Hz, 6 H) ppm.
13 C NMR: δ = 157.5, 130.4, 129.8, 125.5, 124.6, 111.4, 64.9, 14.7 ppm.
C16H16Br2O2 (400.11) calcd. C 48.03% H 4.03%
found C 48.03% H 3.81%.
(-)-(P)-2,2’-Dibromo-6,6’-diethoxybiphenyl (P-36): Prepared following the same protocol,
starting from (-)-(P)- 6,6’-dibromobiphenyl-2,2’-diol (31); m.p. 83 - 84 °C; [ ] = -46.3
(c = 1.0, acetone).
(+)-(M)-2,2’-Dibromo-6,6’-diethoxybiphenyl (M-36): Prepared following the same
protocol, starting from (+)-(M)- 6,6’-dibromobiphenyl-2,2’-diol (31); m.p. 81 - 83 °C; [ ] 20
α D
= +45.9 (c = 1.03, acetone).
4.2 Preparation of 6,6’-Dibromobiphenyl-2,2’-dicarboxylic
Acid and Derivative Thereof
(±)-(PM)-6,6’-Dibromobiphenyl-2,2’-dicarboxylic acid (37): At -75 °C, butyllithium (43
mmol) in hexane (29 mL) was added dropwise to a solution of 2,2’,6,6’-tetrabromobiphenyl
(30; 10 g, 21 mmol) in tetrahydrofuran (0.10 mL). The resulting white suspension was then
poured on an excess of freshly crushed dry ice before being treated, at 25 °C, with 2.0 M
hydrochloric acid (50 mL, 0.10 mol). The volatiles were removed and the beige solid residue
was recrystallized from methanol to afford colorless prisms; m.p. 279 - 281 °C "decomp.";
yield: 7.70 g (90%).
1 H NMR (DMSO-d6): δ = 7.90 (dd, J = 8.0, 1.0 Hz, 2 H), 7.82 (dd, J = 8.0, 1.3 Hz, 2
H), 7.34 (t, J = 8.0 Hz, 2 H), 3.10 (s, 2H) ppm.
α
20
D