4-Methylbenzyl alcohol → Tris(p-methylbenzyl)sulfonium tetrafluoroborate

Participants

Reaction Steps

85.1 g (0.351 mol) of di-(p-methylbenzyl) sulfide and 51.5 g (0.421 mol) of p-methylbenzyl alcohol are initially introduced into 250 ml of methylene chloride under an N2 atmosphere in a reaction vessel (750 ml) provided with a stirrer and thermometer. 142.7 g of an approximately 54% by weight HBF4 solution in diethyl ether is added dropwise at an internal temperature of 20°-30° C. in the course of 40 min, while stirring. The reaction mixture is stirred at RT for 2 h. The reaction mixture is diluted with methylene chloride and extracted 4 times by shaking with deionized water (pH 5-6). The organic phase is dried with MgSO4 and the methylene chloride is removed on a rotary evaporator. The product, which has not been completely freed from methylene chloride, is stirred in 250 ml of toluene at RT for about 1 h and then at 0°-5° C. for 1 h. The crystals which have now precipitated are filtered off with suction and washed with a little toluene. The product is dried under a high vacuum at room temperature for 19 h. 118.6 g of tris-(p-methylbenzyl)-sulfonium tetrafluoroborate are obtained as white crystals of melting point 168°-170° C.

Provenance & Evidence