1. Recent reviews about crown ether and related systems: (a) Izatt, R. M.; Pawlak, K.; Bradshaw, J. S.; Bruening, R. L. Chem. Rev. 1991, 91, 1721–2085; (b) Izatt, R. M.; Bradshaw, J. S.; Pawlak, K.; Bruening, R. L.; Tarbet, B. J. Chem. Rev. 1992, 92, 1261–1354; (c) Izatt, R. M.; Pawlak, K.; Bradshaw, J. S.; Bruening, R. L. Chem. Rev. 1995, 95, 2529–2586; (d) Gokel, G. W. Crown Ether and Cryptands; Royal Society of Chemistry: Cambridge, 1991; (e) Zhang, X. X.; Bradshaw, J. S.; Izatt, R. M. Chem. Rev. 1997, 97, 3313–3361; (f) Balzani, V.; Credi, A.; Raymo, F. M.; Stoddart, J. F. Angew. Chem., Int. Ed. Engl. 2000, 39, 3349–3391.
2. Starks, C. M.; Liotta, C. Phase Tranfer Catalysis Principles and Techniques; Academic Press: New York, 1978; Chapter 3, pp. 57–90.
3. Pedersen, C. J. J. Am. Chem. Soc. 1967, 89, 2495–2496, 7017–7036.
4. Facile separation of the cis isomers of dicyclohexyl-18-crown-6
5. Crystal structures of two isomers of dicyclohexyl-18-crown-6