Acetic Anhydride → 3,7-Di-t-butyldibenziodolium Trifluoromethanesulfonate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Into a 250 ml 3-neck round bottom flask equipped with a mechanical stirrer, thermometer, and inlet was charged with agitation, 4.0 grams (18.8 mmol, 1.0 eq) of potassium iodate, 5.0 grams (18.8 mmol, 1.0 eq) of 4,4'-di-t-butylbiphenyl, and 20 mL of acetic anhydride to form a mixture which was cooled to 0° C. To the mixture was added 5.63 grams (3.32 mL, 37.5 mmol, 2.0 eq) of triflic acid dropwise at such a rate that the reaction temperature did not exceed 10° C. The temperature was kept below 10° C. during the addition by the use of a cooling bath. The reaction mixture was never homogeneous and the 4,4'-di-t-butylbiphenyl did not appear very soluble in the reaction mixture. The reaction mixture turned dark almost immediately upon addition of the triflic acid. The mixture was stirred for about 14 hours at room temperature. The reaction was quenched with approximately 60 mL of water and extracted with methylene chloride. The methylene chloride layer was washed with saturated aqueous sodium bicarbonate solution and concentrated in vacuo. The residue was a dark viscous oil. This material was soluble in ether and could be precipitated with hexanes; however, the precipitate was a brown amorphous powder. Titration with acetone gave a tan solid 0.2 gram (2% yield). Melting point=233°-234° C.

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