Wixe T, Wallentin C.-J, Johnson MT, Fristrup P, Lidin S, Wärnmark K * Lund University,
Sweden and Technical University of Denmark, Kongens Lyngby, Denmark
Synthesis of an Orthogonal Topological Analogue of Helicene.
Chem. Eur. J. 2013;
19: 14963-14969
Key words
helical structures - Friedländer condensation
Significance
Helical molecular systems, both natural and unnatural, continue to capture the interests
of chemists. Using an enantiomerically pure bicyclic moiety to appropriately place
kinks into the system, Wärnmark and co-workers report the synthesis of helical structure
1, an orthogonal topological analogue of helicene.
Comment
The synthesis of 1 is accomplished by repeated employment of a two-step set of reactions consisting
of (1) ring-opening hydrolysis in acid and (2) Friedländer condensation with a chiral
bicyclic ketone. By this strategy, monomer 2 is converted into ring-opened trimer 3, which is converted into trimeric ketone 4. Condensation of 4 and 3 affords the helical target 1.
