A. Tsuda et T. Oshima, CATION-BINDING ACCELERATION OF DIELS-ALDER REACTION OF QUINOCROWN ETHERS WITH CYCLOPENTADIENE, New journal of chemistry, 22(10), 1998, pp. 1027-1029
Diels-Alder reactions of 15-21 membered quinocrown ethers la-e with cy
clopentadiene have been accelerated by the addition of alkali, alkalin
e-earth, and scandium perchlorates, reflecting the selective cation-bi
nding abilities of crown ethers.