Synthesis of[4]Dendralene Derivatives PossessingQuadruple 1,3-Dithiol-2-ylidenes and Transformation to a Trimethylenecylopentenein an Oxidation State

New derivatives of [4]dendralene with redox-active 1,3-dithiol-2-ylidene units were synthesized. X-ray crystal structure analysis of the dibenzo-tetramethyl derivative revealed that the molecule takes a conformation in which two vinyl-extended TTF moieties are significantly inclined to each other. The octamethyl derivative underwent cyclization with skeletal rearrangement in the dicationic state to give the corresponding dicationic trimethylenecylopentene, which exhibited a simultaneous two-electron reduction wave at a significantly negative potential of −0.42 V (V vs Fc/Fc⁺).