Tetrathiafulvalene ring synthesis

This chapter deals with the synthesis, reactivity, and characterization of five-membered heterocycles containing two ring sulfur atoms (1,3-dithiole derivatives) and is a review of the literature in the period 1995-2006. Previous reviews covered the literature till 1982 (CHEC(1984)) <1984CHEC(6)813> and 1995 (CHEC-II(1996)) <1996CHEC-11(3)607>. Among 1,3-dithiole compounds, 1,3-dithiolylium ions 1, mesoionic l,3-dithiol-4-ones 2, mesoionic 1,3-dithiole-4-thiones 3, 1,3-dithioles 4, 1,3-dithiolanes 5, and the tetrathiafulv alene (TTF) system 6 as a special class of compounds are discussed. 7l-Extended tetrathiafulvalenes (7t-exTTFs) containing more than one conjugated multiple bond between two 1,3-dithiole moieties are also discussed, in conjunction with 6. 

Six articles cover general aspects of heterocyclic chemistry 1,3-dipolar cycloreversions, syntheses with arylnitrenes and a-metallated isocyanides, and photo-oxygenation of nitrogen heterocycles,while others deal with more specialized subjects, i.e. preparation and use of halogeno-lactones, aspects of the chemistry of furan, 1-hydroxy-indoles, ring-opening of azoles by the action of amines, " the use of 2-chlorobenzoxazolium (1) and other heterocyclic onium salts for dehydration and condensation reactions," the synthesis of monosub-stituted tetrathiafulvalenes (2), cycloadditions of azoles containing three heteroatoms,sydnone imines (3), the conversion of acyl-benzofuroxans into nitro-indazoles (cf. p. 199), and advances in the chemistry of pyrrolizidine " and indolizine." ... 

Thiaselenin rings fused to tetrathiafulvalenes such as 125 have been prepared by a multistep sequence (Scheme 31) <2002JOC4218>. The key step in the reaction scheme involves an intramolecular transalkylation reaction (Scheme 32). In this reaction the tosylate group in 123 is displaced by iodide allowing an intramolecular displacement by selenium. Cyclization leads to an intermediate selenonium salt 126, which is dealkylated by iodide affording 124. Standard reactions forming the tetrathiafulvalene complete the synthesis. 

One line of interest in catenanes is to use them to study details of electron transfer, by having an electron donor in one ring, an electron acceptor in another (Figure 4-12). The first step in this programme was the synthesis of a [2]-catenane with a tetrathiafulvalene unit incorporated into one of the rings. The required catenane... 

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