Macrocyclic 1,4-Diketones: Versatile Intermediates for the Chemical Synthesis of Complex, Congested and Constrained Molecules

Our group has recently demonstrated that macrocyclic 1,4-dketones can be converted into highly
strained arene-bridged systems, which represent (macrocyclic) benzenoid segments of armchair
carbon nanotubes (CNTs). This non-cross-coupling-based approach enables the incorporation of
strategically placed (aryl) halides that can later be engaged in programmed carbon-carbon bond
forming reactions, resulting in longitudinal pi-extension of benzenoid CNT segments to polycyclic
aromatic hydrocarbon (PAH) segments. The success of this approach is due to a
diastereoselective Grignard reaction, which is, in turn, dependent on the size of the macrocyclic
system(s) employed. Recent work that takes advantage of this size-dependent
diastereoselectivity and its application to the synthesis of functionalized bent arene units, highly
strained benzenoid macrocycles, and polyfunctionalized cyclobutanes will be discussed.