Journal of Inclusion Phenomena and Macrocyclic Chemistry 36: 67–78, 2000. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 67 Synthesis and Host Properties of (1,3)-p-tert-Butylcalix[5]crown-6 Derivatives Incorporating the 1,1 ′ -Binaphthalene-2,2 ′ -dioxy Subunit SALVATORE CACCAMESE 1 , ANNA NOTTI 2 , SEBASTIANO PAPPALARDO 1⋆ , MELCHIORRE F. PARISI 2 and GRAZIA PRINCIPATO 1 1 Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy; 2 Dipartimento di Chimica Organica e Biologica, Università di Messina, Salita Sperone 31, I-98166 Vill. S. Agata, Messina, Italy (Received: 7 October 1998; in final form: 31 December 1998) Abstract. Alkylation of p-tert-butylcalix[5]arene (1) with 2,2 ′ -bis(5-tosyloxy-3-oxa-1-pentyloxy)- 1,1 ′ -binaphthalene ((±)-2) in the presence of CsF affords selectively racemic 1,3-bridged calix[5] crown-6-triol 3, along with very small amounts of the (1,2)-bridged regioisomer 4. Compound 3 has been converted into tri-methoxy and tri-α-picolyloxy derivatives 5 and 6, respectively, by exhaustive alkylation with the appropriate electrophile and base. The direct separation of the enantiomers of racemates 3 and 6 was achieved by HPLC, using a chiral stationary phase (Chiralpak AD). Hosts 5 and 6 are able to selectively form 1 : 1 endo-cavity complexes with the linear RNH + 3 ions. Key words: Chiral calixarene crown ethers, separation of enantiomers, molecular recognition, RNH + 3 inclusion complexes. 1. Introduction Calixarenes [1, 2], termed by Shinkai ‘the third generation of supramolecules’ [3, 4], offer a broad range of possible chemical modifications, including the prepar- ation of calixarenes endowed with chiral groups at the upper or lower rim [5], as well as inherently chiral calixarenes [6]. To date, only a few examples have been reported on the use of binaphthyl reagents to introduce axial chirality into calix- arene host molecules, these studies being confined to calix[4]arenes. Earlier Kubo et al. have described the synthesis and colorimetric recognition properties of chro- mogenic 1,1 ′ -binaphthyl-derived calix[4]crown ethers [7, 8], and more recently Stibor et al. have reported the synthesis of upper or lower rim binaphthyl-bridged calix[4]arenes as potential chiral hosts for molecular recognition and catalysis [9, 10]. ⋆ Author for correspondence.