A series of carba- or oxa[5]-, [6]-, [7]-, and -[19]helicene (di)thiols was prepared. The Miyazaki-Newman-Kwart rearrangement of (dimethylcarbamothioyl)oxy (oxa)helicenes in a flow reactor or nucleophilic substitution of dichloro (oxa)helicenes with alkanethiolates were used in the sulfanylation step. Despite the high temperatures employed in this key step, no conformational scrambling was observed during the asymmetric synthesis of the diastereo- and enantiopure oxahelicenes. Single-molecule conductivity of the longest oxa[19]helicene dithiol derivative was studied by the scanning tunneling microscopy break-junction method.

Department of Inorganic Chemistry Faculty of Science Charles University Prague Hlavova 2030 8 128 43 Prague 2 Czech Republic

Department of Organic Chemistry Faculty of Science Charles University Prague Hlavova 2030 8 128 43 Prague 2 Czech Republic

Department of Physical and Macromolecular Chemistry Faculty of Science Charles University Prague Hlavova 2030 8 128 43 Prague 2 Czech Republic

Department of Physics Faculty of Electrical Engineering CTU Prague Technická 2 166 27 Prague 6 Czech Republic

Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Flemingovo nám 2 166 10 Prague 6 Czech Republic

References provided by Crossref.org

Stereocontrolled Synthesis of Chiral Helicene-Indenido ansa- and Half-Sandwich Metal Complexes and Their Use in Catalysis

Cyclotrimerization Approach to Symmetric [9]Helical Indenofluorenes: Diverting Cyclization Pathways

Helical Bilayer Nanographenes: Impact of the Helicene Length on the Structural, Electrochemical, Photophysical, and Chiroptical Properties