Change of connectivity on catenane ring: ring expansion by annulation-ring scission sequence.
[reaction: see text]. Ring expansion of a catenane without destruction of the interlocked structure was attained by Diels-Alder reaction followed by ozonolysis. Annulation by Diels-Alder reaction introduced a C4 fragment onto the ring, and the ozonolysis scissored the resulting double bond to expand the catenane ring. The annulation-ring scission sequence provides a general approach for changing the connectivity on a catenane ring without destroying the interlocked structure.
Watanabe
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Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531, Japan.
Kihara
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Takata
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