Abstract
A general synthetic methodology for the preparation of functionalized (hetero)helicenes has been developed. It employs the sequence of a double propargyl organometallics (Li, Mg, Ga/In) addition to a tolan-2,2'-dialdehyde-type intermediate, a cobalt-catalyzed [2 + 2 + 2] cycloisomerization of a triyne intermediate, and a double silica gel-assisted acetic acid elimination to receive pentahelicene followed by palladium catalyzed Suzuki-Miyaura coupling.