134
M. Zaidlewicz, A. Wolan / Journal of Organometallic Chemistry 657 (2002) 129ꢀ135
/
DMSO-d6, d 30.31 (CH2), 34.95 (CH2), 127.04 (CHAr),
133.99 (CHAr), 142.58 (CAr), 172.38 (COOH); 11B-
NMR, DMSO-d6, d 30.38; Anal. Calc. for C9H11BO4:
C, 55.72; H, 5.72. Found: C, 55.46; H, 5.71%.
4.5.6. Methyl 3-[4-(4,4,5,5-tetramethyl-
[1,3,2]dioxaborolan-2-yl)phenyl]propanoate (12c).
Typical procedure
The ester 11c (0.73 g, 3 mmol) was added to a
suspension of PdCl2(dppf) (73 mg, 0.09 mmol) in
degassed [bmim][BF4] (3 cm3), under argon atmosphere,
and the mixture was heated to 100 8C with vigorous
stirring. The deep-red solution was cooled to ambient
temperature, potassium acetate (0.89 g, 9 mmol), and 10
(0.84, 3.3 mmol), were added. The mixture was heated
with vigorous stirring at 100 8C for 2 h. It was cooled
4.5.2. Hydrolysis of 9c
Ethyl 3-(4-[1,3,2]dioxaborinan-2-yl-phenyl)propano-
ate (1.17 g, 4.5 mmol) was refluxed with 3 M NaOH
(20 cm3) for 3 h. The solution was cooled to 0 8C and
acidified with conc. HCl. The product, a white solid
which, precipitated was filtered off, washed with water,
and extracted with petroleum ether (5ꢂ
combined extracts were washed with water (2ꢂ
/
15 cm3). The
15 cm3),
and dried, 0.71 g, 82%, m.p. 168ꢀ
/
170 8C. Spectroscopic
/
data identical as above.
and dried over magnesium sulfate. Evaporation of the
solvent afforded an oily product, 0.77 g, 88%; 1H-NMR,
CDCl3, d 1.33 (s, CH3, 12H), 2.63 (t, Jꢃ
2H), 2.96 (t, Jꢃ8.2 Hz, CH2, 2H), 3.66 (s, CH3, 3H),
7.21 (d, Jꢃ8.2 Hz, CH, 2H), 7.73 (d, Jꢃ8.2 Hz, CH,
2H); 13C-NMR, CDCl3, d 24.82 (CH3), 31.09 (CH2),
35.47 (CH2), 51.55 (OÃCH3), 83.66 (OÃC), 127.67
(CHAr), 135.03 (CHAr), 143.80 (CAr), 172.18 (CÄO);
11B-NMR, CDCl3, d 31.87; A sample was purified by
column chromatography on silica gel (hexaneꢀCH2Cl2ꢀ
/
7.2 Hz, CH2,
4.5.3. Methyl 3-(4-bromophenyl)propanoate (11c).
Typical procedure
/
/
/
Methanol (10 cm3) was added carefully to thionyl
chloride (10.71 g, 90 mmol) at 0 8C, followed by 2c (15
mmol). The mixture was refluxed for 2 h, the solvent
and excess thionyl chloride were evaporated and the
remaining oil was dissolved in Et2O (100 cm3). The
/
/
/
/
/
organic solution was washed with water (3ꢂ
/
20 cm3),
AcOEt, 70/20/10). Anal. Calc. for C16H23BO4: C, 66.23;
H, 7.99. Found: C, 65.98; H, 7.95%.
and dried over magnesium sulfate. The solvent was
removed, and product was isolated by distillation, 2.9 g,
80%, 92 8C/0.4 mmHg; 1H-NMR, CDCl3, d 2.60 (t, Jꢃ
/
4.5.7. Methyl 4-[4-(4,4,5,5-tetramethyl-
[1,3,2]dioxaborolan-2-yl)phenyl]butanoate (12d)
Prepared from 11d following the procedure described
1
above, oil, 0.81 g, 89%; H-NMR, CDCl3, d 1.33 (s,
7.8 Hz, CH2, 2H), 2.90 (t, Jꢃ7.8, CH2, 2H), 3.66 (s,
/
CH3, 3H), 7.06 (d, Jꢃ
/
8.1 Hz, CH, 2H), 7.39 (d, Jꢃ8.1
/
Hz, CH, 2H); 13C-NMR, CDCl3, d 30.06 (CH2), 35.21
(CH2), 51.48 (CH3), 119.91 (CAr), 129.92 (CHAr), 131.54
CH3, 12H), 1.95 (m, CH2, 2H), 2.32 (t, Jꢃ
2H), 2.66 (t, Jꢃ7.8 Hz, CH2, 2H), 3.66 (s, CH3, 3H),
7.19 (d, Jꢃ8.2 Hz, CH, 2H), 7.74 (d, Jꢃ8.2 Hz, CH,
2H); 13C-NMR, CDCl3, d 24.78 (CH3), 26.23 (CH2),
33.25 (CH2), 35.22 (CH2), 51.39 (OꢀCH3) 83.57 (OꢀC),
127.86 (CHAr), 134.88 (CHAr), 144.69 (CAr), 173.76
(Cꢃ
O); 11B-NMR, CDCl3, d 31.21; A sample was
/
7.6 Hz, CH2,
(CHAr), 139.31 (CAr), 172.80 (CÄ
/
O). Lit. [26], b.p. 154ꢀ
/
/
155 8C/16 mmHg.
/
/
/
/
4.5.4. Methyl 4-(4-bromophenyl)butanoate (11d)
Prepared from 2d following the procedure described
/
1
above. Yield, 83%, b.p. 110 8C/0.4 mmHg; H-NMR,
purified by column chromatography on silica gel
(hexane/CH2Cl2/AcOEt, 70/20/10). Anal. Calc. For
C17H25BO4 C 67.12, H 8.28. Found: C 66.80, H 8.27.
CDCl3, d 1.92 (m, CH2, 2H), 2.32 (t, Jꢃ
/
7.6 Hz, CH2,
2H), 2.60 (t, Jꢃ7.4, CH2, 2H), 3.66 (s, CH3, 3H), 7.04
/
(d, Jꢃ
/
8.4 Hz, CH, 2H), 7.39 (d, Jꢃ8.4 Hz, CH, 2H);
/
13C-NMR, CDCl3, d 26.22 (CH2), 33.17 (CH2), 34.43
(CH2), 51.48 (CH3), 119.70 (CAr), 130.17 (CHAr), 131.40
4.5.8. Methyl 5-[4-(4,4,5,5-tetramethyl-
[1,3,2]dioxaborolan-2-yl)-phenyl]pentanoate (12e)
Prepared from 11e following the procedure described
1
above, oil, 0.82 g, 86%; H-NMR, CDCl3, d 1.33 (s,
CH3, 12H), 2.31 (m, CH2, 4H), 2.63 (m, CH2, 4H), 3.65
(CHAr), 140.26 (CAr), 173.72 (CÄ
/
O). Lit. [24], b.p.
90 8C/0.05 mmHg.
4.5.5. Methyl 5-(4-bromophenyl)pentanoate (11e)
Prepared from 2e following the procedure described
above. Yield, 73%, 115 8C/0.2 mmHg; 1H-NMR,
(s, CH3, 3H), 7.17 (d, Jꢃ
/
8.2 Hz, CH, 2H), 7.71 (d, Jꢃ
/
8.2 Hz, CH, 2H); 13C-NMR, CDCl3, d 24.48 (CH2),
24.78 (CH3), 30.60 (CH2), 33.84 (CH2), 35.66 (CH2),
CDCl3, d 1.61 (m, CH2, 4H), 2.35 (t, Jꢃ
/
7.2 Hz, CH2,
51.37 (OÃ
(CHAr), 145.46 (CAr), 173.94 (CÄ
d 31.50; A sample was purified by column chromato-
graphy on silica gel (hexaneꢀCH2Cl2ꢀAcOEt, 70/20/10).
/
CH3), 83.42 (OÃ
/
C), 127.78 (CHAr), 134.82
2H), 2.59 (t, Jꢃ7.2, CH2, 2H), 3.63 (s, CH3, 3H), 7.05
/
/
O); 11B-NMR, CDCl3,
(d, Jꢃ
/
8.3 Hz, CH, 2H), 7.40 (d, Jꢃ8.3 Hz, CH, 2H);
/
13C-NMR, CDCl3, d 24.39 (CH2), 30.64 (CH2), 33.77
/
/
(CH2), 34.85 (CH2), 51.47 (CH3), 119.44 (CAr), 130.12
Anal. Calc. for C18H27BO4: C, 67.94; H, 8.55. Found: C,
67.61; H, 8.54%.
(CHAr), 131.30 (CHAr), 140.99 (CAr), 173.87 (CÄ
/
O).