Chemistry Reference
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Fig. 8 The two applied approaches to catenane synthesis prior to 1983. (a) The first statistical
synthesis [
58
] relied upon the macrocyclization of a linear compound (
I
) in the presence of a
deuterated cycloalkane (
III
) to achieve small amounts of the catenane
V
.(b) The first example [
59
]
of directed synthesis by covalent templation was a catenane that formed after cleaving the covalent
bonds around the aromatic core in compound 16. Reproduced with permission from [
58
] (copy-
right 1960 American Chemical Society), [
59
] (copyright 1964 Wiley-VCH)
strip approach had been proposed in the late 1950s independently by both
Wasserman [
51
] and van Gulick [
69
] in an article that was denied publication in
Tetrahedron
at the time (ca. 1961) only to be given the light of day much later on in
a special issue of the
New Journal of Chemistry
published in 1993 under the
editorship of David Walba. A more detailed history of the M
obius strip approach
was discussed by Walba [
54
]. In 1981, Walba [
70
] made this approach look more
realistic through the use of tetra-hydroxymethylethylene (THYME) polyethers. The
bis-macrocyclization of a THYME-based molecule resembling a three-rung ladder
can result in a mixture of wreath-like macrocycles with some number of half-twists
(Fig.
9
). Isolation of the wreath with two half-twists and severing the three ladder
rungs would yield a [2]catenane. Walba isolated the zero-twist cylinder and
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