Calix[4]arene‐Based Bis[2]catenanes: Synthesis and Chiral Resolution

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Abstract
The exclusive formation of hydrogen‐bonded dimers between tetraaryl and tetratosylurea calix[4]arenes has been used to prepare a series of ten “bisloop” tetraurea calix[4]arenes 3, in which adjacent phenylurea groups are covalently linked through α,ω‐dioxyalkane chains. This dimerization with tetratosylurea 2 as template preorganizes the alkenyl residues of tetra(m‐alkenyloxyphenyl) ureas 1 and enables their selective connection in high yield (up to 95 %) by olefin metathesis followed by hydrogenation. The “bisloop” calixarenes 3 also exclusively form heterodimers with 1. Thus, in a separated metathesis/hydrogenation sequence, a series of 14 cyclic bis[2]catenanes 4, in which two calix[4]arenes are connected through their wide rims by two pairs of interlocked rings (total size 29 to 41 atoms), were prepared in yields of up to 97 %. Optical resolution of these chiral bis[2]catenanes was studied by HPLC on chiral stationary phases. The single‐crystal X‐ray structure of one example (4(P,10)) confirmed the interlocking rings and revealed that the hydrogen‐bonded dimeric capsule of the calix[4]arene can be “completely” opened.

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