Oxygen → 3,6-Bis(triisopropylsilyl)-9H-carbazole

Participants

Reaction Conditions

Reaction Steps

A 500 ml dry round bottom flask was charged with 9-benzyl-3,6-bis-triisopropylsilanyl-9H-carbazole 4 (23.0 g, 0.04 mol) and the oil was suspended in 100 ml DMSO. The suspension was cooled in an ice water bath (˜15° C.) and 1M KOBu-t in THF (240 ml, 0.24 mol) was added via a syringe under nitrogen. Oxygen started to bubble in the mixture and the nitrogen line was suppressed. While the oxygen bubbling was taking place, the mixture was left to warm up to ˜20° C. and cooling continued with only water. The oxygen bubbling continued until the starting material (TLC) disappeared, i.e., after ˜30 min. Water was added to the mixture and the mixture was extracted with 5×200 ml ethylacetate. To remove the benzoic acid organic layer, the mixture was washed with sat. NaHCO3, followed by brine washing. The organic layer was then dried over Na2SO4, filtered, concentrated, and purified over a 330 g SiO2 column with hexane and hexane:ethylacetate (95:5) eluents. Appropriate fractions were collected to yield a white solid of 3,6-bis-triisopropylsilanyl-carbazole 5 10.0 g (54%).

Provenance & Evidence