Benzene → 4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)phenol

Temperatur

80 °C

440 mg (2 mmol) of p-iodophenol were placed in a Schlenk flask with 100 ml of dry benzene and 0.17 ml of triethyl borate (1 mmol). The solution was heated for 1.5 h under an inert atmosphere (argon) at 80° C. and then the benzene and ethanol formed were distilled off the product after raising the oil bath temperature to 100° C. To the liquid in the Schlenk was then added 10 ml of activated catalyst (PdCl2[dppf].CH2Cl2) solution, prepared as described in Example 26, followed by 0.35 ml (2.4 mmol) of pinacolborane. No frothing indicating H2 evolution, which would suggest free phenol groups, was observed. The reaction solution was then heated at 80° C. for 7.5 h before removal of an aliquot for gc analysis. This sample was washed in ethyl acetate with 10% brine as described elsewhere. Only two peaks were observed in the gc with retention time longer than 2 minutes and these corresponded to phenylboronic acid pinacol ester (area approx. 7.5%) and with the desired product contributing the remaining area (92.5%).

1. distillationwere distilled off the product
2. temperatureafter raising the oil bath temperature to 100° C
3. additionTo the liquid in the Schlenk was then added 10 ml of activated catalyst (PdCl2[dppf].CH2Cl2) solution
4. customprepared
5. temperatureThe reaction solution was then heated at 80° C. for 7.5 h before removal of an aliquot for gc analysis
6. washThis sample was washed in ethyl acetate with 10% brine

ORD-Eintrag

ord-7f8cf2360b4a4d1e98ebd43c262fe257

Quelldatensatz

uspto-grants-2006_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07122694B2