ChemInform Abstract: The Thyme Polyethers: An Approach to the Synthesis of a Molecular Knotted Ring.

Abstract

The compound (VII) is gradually synthesized as described in the scheme.

A closed linkage mechanism having the shape of a discrete Möbius strip

“…Table 1 shows the values of cn, twist (described later; when c = cn), E bend , and E dipl (oriented cases) for some n ≥ 6. If considering all Kaleidocycles, including non-extreme cases, E bend appears to have a minimum value when the positions of γi are as planar as possible and have a higher symmetry 11 , and an extreme n-Kaleidocycle (except when n = 7) does not provide even a local minimum.…”

An Introduction to the Mechanical Bond

“…116 These founders of molecular topology realized that molecules resembling Möbius strips could be cut (Figure 1.10a) into catenated and knotted structures, depending on the location of the cut and the number of half-twists in the strip. Walba [117][118][119] made this approach look more realistic in the early 1980s when he began syn thesizing wreath-like macrocycles from tetrahydroxy-methylethylene (THYME) polyethers resem bling a three-rung ladder. If the wreath with two half-twists could be isolated and its ladder rung crosslinks severed in half (Figure 1.10b), a [2]catenane would be the result.…”

“…He verified experimentally that two macrocycles are obtained by cutting the cylinder in half by ozonolysis of the THYME double bonds, while the same action on the Möbius strip leaves it in one piece as a larger macrocycle. 119 No double half-twist Möbius strip that would lead to the [2]catenane has been reported, however. See Sections 2.1-2.2 for a more detailed discussion of these historical landmarks in mechanostereochemistry.…”