Lanthanide triflates and a series of hexadentate chiral ligand complexes were synthesized. X-ray-quality crystals were obtained from mixtures of the lanthanide complexes, which were helical in shape. The complexes showed Lewis acidity and catalyzed the enantioselective Diels-Alder reaction of electron-rich siloxydienes. The complexes were stable enough to be stored at ambient temperature on a laboratory bench and retained their Lewis acidity even after a month.
Keywords: Diels-Alder reaction; Lewis acid; asymmetric synthesis; helical structure; lanthanides.
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