Vinylogs of tetrathiafulvalene (TTF) bearing four 1,4-dithiafulven-6-yl substituents : Novel highly extended and sulfur-rich π-donors
摘要:
The title compounds 1 were synthesized from the mono-diEt-acetal of acetylenedicarbaldehyde and 2-thioxo-1,3-dithioles through three key steps: cycloaddition, dimerization-desulphurization of the resulting thials, and after deketalization, fourfold Wittig olefination of the tetraformyl TTF-vinylogs 4 with the P-ylids Walpha-gamma bearing the 1,3-dithiol-2-ylidene moiety. Cyclic voltammetry shows that these compounds are very strong pi-donors and good precursors of conducting cation-radical salts.