5-fluoro-2- (4,4,5,5, - tetramethyl-1,3,2-dioxaborolan-2-yl) benzaldehyde
SYNTHESIS 94)
2-bromo-5-fluorobenzaldehyde 26.1g (129mmol), 4,4,4 ', 4', 5,5,5 ', 5'- octamethyl-2,2'-bi-1,3,2- dioxaborolane 39.2g (154mmol), N of potassium acetate 25.2g (257mmol) and [1,1'-bis (diphenylphosphino) ferrocene] dichloro palladium (II) dichloromethane adduct 5.25g (6.43mmol), It was stirred for 16 hours at 100 ℃ the N- dimethylformamide (200mL) solution.Water was added to the reaction mixture and extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, the crude product obtained was concentrated and purified by silica gel chromatography (5% -25% ethyl acetate / hexanes), the title compound 16.6g of (52%) pale yellow crystals It was obtained as a.
1 H-NMR (300MHz, CDCl3) δ1.38 (12H, s), 7.27 (1H, td, J = 2.7,8.1Hz), 7.65 (1H, dd, J = 2. 7,9.3Hz), 7.92 (1H, dd, J = 6.3,8.1Hz), 10.62 (1H, d, J = 3.3Hz),
melting point 55-58 ℃.
Starting materials
2-Bromo-5-fluorobenzaldehyde
- CAS Number 94569-84-3
Identifiers | |
---|---|
73183-34-3 | |
Jmol-3D images | Image |
PubChem | 2733548 |
Properties | |
C12H24B2O4 | |
Molar mass | 253.94 g·mol−1 |
Melting point | 137 to 140 °C (279 to 284 °F; 410 to 413 K) |
Preparation and structure
This compound may be prepared by reacting tetrakis(dimethylamino)diboron with pinacol in acidic conditions.[1] The B-B bond distance is 1.711(6) Å.[2]References
- Tatsuo Ishiyama, Miki Murata, Taka-aki Ahiko, and Norio Miyaura (2004). "Bis(pinacolato)diboron". Org. Synth.; Coll. Vol. 10, p. 115
- C.Kleeberg, A.G.Crawford, A.S.Batsanov, P.Hodgkinson, D.C.Apperley, Man Sing Cheung, Zhenyang Lin, T.B.Marder "Spectroscopic and Structural Characterization of the CyNHC Adduct of B2pin2 in Solution and in the Solid State" J. Org. Chem 2012, vol. 77, pp. 785.doi:10.1021/jo202127c
- Xinyu Liu "Bis(pinacolato)diboron" Synlett 2003, pp 2442–2443. doi:10.1055/s-2003-43344
- http://www.google.fr/patents/WO2010110400A1?cl=en&hl=fr
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////////////5-fluoro-2- (4,4,5,5, - tetramethyl-1,3,2-dioxaborolan-2-yl) benzaldehyde
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