Baskets, covered baskets, and basket balls: corannulene based cyclophanes as fullerene mimics T. Jon Seiders, Kim K. Baldridge and Jay S. Siegel p Department of Chemistry, University of CaliforniaÐSan Diego, La Jolla, CA 92093-0358, USA Received 10 October 2000; accepted 9 January 2001 Abstract ÐThree cyclophanes based on corannulene have been synthesized. Aryl and alkyl groups have been strapped across the corannu- lene nucleus and a dimeric corannulene cyclophane has been prepared. The structure and conformational analysis of these compounds have been elucidated by NMR and ab initio quantum mechanical methods. The speci®c NMR effect of the corannulene system on the adjacent nuclei is discussed. These cyclophanes exhibit novel structures and are prototypical fullerene mimics. q 2001 Published by Elsevier Science Ltd. Fullerene fragments, 1 such as corannulene, inspire the design of several cyclophane motifs: 2 covered baskets, 3 ansa baskets 4 and `basket balls' 5 Fig. 1). Corannulene based cyclophanes may serve as mimics and receptors of fullerenes as well as precursors to endohedral fullerene complexes. Receptors of fullerenes based on calixarenes, 6 cyclotriveratralenes, 7 and g-cyclodextrins 8 have been previously reported. Speci®cally, Rubin has reported a cyclophane that may serve as a precursor to an endohedral fullerene complex. 9 Recently, we have developed a high yielding solution phase synthesis of corannulene and alkyl derivatives that can serve as building blocks for the construction of these fullerene cognates. 10 Using these building blocks, cyclophanes 1 ± 3) based on corannulene have been synthesized and exhibit interesting structure and NMR properties. The diametrically opposed relationship between the 1 and 6 positions of coran- nulene constrains the linker to cross directly above the corannulene nucleus and offers a good way to probe the properties of the concave face of the bowl. Although Tetrahedron 57 2001) 3737±3742 Pergamon TETRAHEDRON 0040±4020/01/$ - see front matter q 2001 Published by Elsevier Science Ltd. PII: S0040-402001)00242-3 Figure 1. Cyclophane motifs: covered-basket, ansa-basket and basket-ball. Keywords: cyclophanes; corannulene; fullerene mimic. p Corresponding author. Tel.: 11-858-534-5659; fax: 11-858-822-0386; e-mail: jss@chem.ucsd.edu