Preparation of Tetrathiafulvalenes (TTF) and their Selenium Analogs-Tetraselenafulvalenes (TSeF).

摘要

Acetylene carboxylic acids reacted with trialkylphosphine-carbon disulfide ylides to produce fair to good yields of 2-trialkylphosphonio-1,3-dithiole-4-carboxylates (4) at temperatures as low as -20 to -30 C. The formation of these zwitterionic products, by a prototropic shift in the ylide, differs from the known reaction of acetylenes, such as ethyl propiolate, with carbon disulfide and tributylphosphine to give tetrathiafulvalene derivatives. The structure of these zwitterionic products was confirmed by alkaline hydrolysis, reaction with benzaldehyde, and their IR and NMR spectra. Alkaline hydrolysis of 4 gave the corresponding carboxyl-substituted 1,3-dithioles. The methine proton of the 1,3-dithiole ring of 4 in DMSO-d6, appeared at 5.41-6.24 as a singlet peak. These methine protons were readily exchanged by deuterium in the presence of methanol-d4, and disappeared from NMR spectra.