Direct Preparation of Rotaxane from Aminoalcohol: Selective<i>O</i>-Acylation of Aminoalcohol in the Presence of Trifluoromethanesulfonic Acid and Crown Ether
Selective O-acylation of aminoalcohols by a bulky acid anhydride in the presence of trifluoromethanesulfonic acid and dibenzo-24-crown-8 afforded [2]rotaxane in high yields. An acid halide could be used as an acylating reagent in the presence of silver trifluoromethanesulfonate.