We repeat the earliest claimed [2]catenane synthesis,
reported
by Wasserman over 60 years ago, in order to ascertain whether or not
a nontemplate, statistical synthesis by acyloin macrocyclization does
indeed form mechanically interlocked rings. The lack of direct experimental
evidence for Wasserman’s catenane has led to it being described
as a “prophetic compound”, a technical term used in
patents for claimed molecules that have not yet been synthesized.
Contemporary synthetic methods were used to reconstruct Wasserman’s
deuterium-labeled macrocycle and other building blocks on the 10–100
g reaction scale necessary to generate, in principle, ∼1 mg
of catenane. Modern spectrometric and spectroscopic tools and chemical
techniques (including tandem mass spectrometry, deuterium nuclear
magnetic resonance (NMR) spectroscopy, and fluorescent tag labeling)
were brought to bear in an effort to detect, isolate, and prove the
structure of a putative [2]catenane consisting of a 34-membered cyclic
hydrocarbon mechanically linked with a 34-membered cyclic α-hydroxyketone.