Tributyl borate → 5,5-Dimethyl-2-(4-octylthiophen-2-yl)-1,3,2-dioxaborinane

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Reaction Conditions

Reaction Steps

Under argon atmosphere, in a three necked flask 3 g (15.28 mmol, 1 eq.) of 3-octylthiophene are dissolved in 30 mL of THF. After having cooled the medium to −78° C., 12 mL (18.34 mmol, 1.2 eq., C=1.6 mol/L) of BuLi are added drop by drop. The reaction is stirred for 1 h at −50° C. Then 8 mL (30.56 mmol, 2 eq.) of tributylborate are added to the medium cooled beforehand to −78° C. The reaction remains under stirring for the following 2 h where the temperature rises to ambient temperature. The mixture is then hydrolysed with a 2 mol·L−1 HCl solution and extracted with 2×50 mL of ethyl ether. During the drying of the organic phase collected on Na2SO4, 4.8 g (45.84 mmol, 3 eq.) of 2,2-dimethyl-1,3-propanediol are added. After 45 min of stirring, the mixture is filtered and concentrated in a rotary evaporator. The purification is carried out on silica column with an eluent [hexane/Et2O: 9/1]. 3.40 g of a yellow oil (yield of 72.0%) are obtained.

Provenance & Evidence