Reactions of ethylene di- and trithiocarbonates with acetylenes. Anomalous reaction with bromocyanoacetylene to give a thioacyl bromide

Designing the Molybdopterin Core through Regioselective Coupling of Building Blocks

“…Compounds 5a and b were reactede ither with ax ylene solution of 4-phenyl-1,3-dithiolane-2-thione or neat to introduce the dithiolene unit. [22] Interestingly,i ntroductiono fadithiolene group in 6 gave ac yclic furan product (7)b earing no THP protection, as well as an alcohol-protected compound (8), with ac ombined yield of approximately 45 %. At room temperature, 8 spontaneously converted to 7 over severald ays.…”

“…The synthesis of pyran-dithiolene precursors Attempting to append the dithioleneunit directly to aterminal acetylene moiety via an electrocyclic process is reported to be inefficient. [16,22,24] The adjacent keto group on 5a and b and 6 activates the acetylene for this reaction, making it am ore efficient unit for the formation of ac yclic, protected dithiolene. The diketo functiono n5 as opposed to the keto-acetal of 6 Figure 3.…”

“…O'connor et al have explored the reactivity of acetylenes with O,S-ethylene dithiocarbonates or ethylene trithiocarbonates to give olefin and O,S-vinylene dithiocarbonates or vinylene trithiocarbonates, respectively. [22] In these reactions, phenylethylenet rithiocarbonate reacts smoothly with an electron-deficient acetylene. [16,22,24] Acetylenes functionalized with the oxalate moiety have only one ethoxyp rotection group and the tetrahydropyrang roup, which are spontaneously removed to form the cyclic products 1a and c.I nc ontrast, acetylenes functionalized with diethyloxy acetate form the cyclic compound much slower, giving two products, 7 and 8.C ompound 7 is the thermodynamically controlled product, whereas 8 is kinetically controlled product.…”

A regioselective synthesis of the dephospho ditholene protected molybdopterin

“…Structurally, compounds 6a and 5a are very similar to 6 and 5 , respectively, with the exception of alcohol and aldehyde groups being protected. Compound 5a contains an acetylene moiety next to an electron withdrawing keto group which makes it suitable for the introduction of a protected dithiolene unit 24, 25 with phenyl-1,3-dithiolane-2-thione 30 resulting in compound 4a in a 58% yield. Compound 4a is a protected form of precursor 4 and contains a protected aldehyde moiety as an acetal, a keto group, a protected dithiolene, and protected alcohol moieties.…”

Novel Dissymmetric Tetrathiafulvalenes as Precursors of Organic Metals: Synthesis, X-ray Crystal Structures, Electrochemical Properties and Study of Their Radical Cations

“…The yield of the first step, although still quite poor (17%), was higher when the 4,5-bis(methoxycarbonyl)-1,3-dithiol-2-one (4) [10] was used for coupling with ketone 1 instead of the analogous thione 3. [11,14] The coupling of ketones 1 and 4 also gives significant amounts of the corresponding symmetrical donors, BET-TTF and tetrakis(methoxycarbonyl)tetrathiafulvalene (TC M-TTF), which were efficiently separated by column chromatography. In spite of the poor yields, this cross-coupling route was our preferred choice for obtaining these TTF-based derivatives, since the precursor ketone 1 is easily prepared in gram amounts.…”