Synthesis, Optical Resolution and Enantiomeric Recognition Ability of Novel, Inherently Chiral Calix[4]arenes: Trial Application to Asymmetric Reactions as Organocatalysts

Newly designed, inherently chiral calix[4]arenes containing amino phenol structures have been synthesized and resolved to optically pure forms. The enantiomeric recognition ability of one chiral calix[4]arene was examined with mandelic acid by H-1 NMR spectroscopy, and we found that the inherently chiral calix[4]arene could be used as a chiral NMR solvating agent to determine the enantiopurity of mandelic acid at ambient temperature. In addition, the chiral calix[4]arenes were used as organocatalysts in asymmetric Michael-type addition reactions of thiophenols, and high catalytic efficiency with low enantioselectivity was observed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)