Thioallylation

Thiophene reacts with ReH7(PPh3)2 aided by the H-acceptor (3,3-dimethyl-l-butene) to give the thioallyl species 113 (92JA10767). Further reaction of 113 with trimethylphosphine yields organometallic products with a cleaved C—S bond. 

Lee ES, Steiner M, Lin R. 1994. Thioallyl compounds potent inhibitors of cell proliferation. Biochim Biophys Acta 1221 73—77. 

Organosulfur compounds present inAllium vegetables, which are either lipid or water soluble, are considered responsible for the beneficial effects of these herbs. Garlic derivatives generally have a thioallyl moiety, whereas onion extracts contain a thiopropyl group with somewhat different chemical properties [14]. 

Asafoetida Ferula foetida Regel R-2-Butyl-l-propenyl disulphide (a mixture of E and Z isomers), 1 -(1 -methylthiopropenyl)-1 -propenyl disulphide, 2-butyl-3-methyl-thioallyl disulphide (both as a mixture of diasteromers)... 

The reaction of thiiranes with BF3 Et20 results in the formation of cyclopentenethiones, by a new type of cyclization via the initially generated thioallyl cations315,316 (equation 52). 

Aged extract of garlic (Allium sativum (-containing biochemically active substances, including thioallyl compounds... 

Marr, F. Frohlich, R. Wibbeling, B. Diedrich, C. Hoppe, D. The synthesis and configurational stability of enantioenriched a-thioallyl-lithium compounds and the stereochemical course of their electrophilic substitution. Eur. 

The conversion of thiophene to THT, via 2,3-dihydrothiophene, is much more difficult. A major difference is that after the first hydride migration a thioallyl ligand is formed (Scheme 74). The poor catalytic activity has been attributed to the fact that THT is a good rt-donor and is not easily displaced by the thiophene so it traps all the available catalytically active species as the bis-THT complex <1998ACR109>. 

The 7] -ruthenium complex 256 is protonated by the weak acid (NH4)Pp6 to give a thioallyl complex (Scheme 84) <20010M1259>. Using (ND4)PF6, it has been shown that the protonation occurs stereospecifically on the endo- xAc of the ring this suggests that the initial protonation takes place on the metal. The weak C-S bond in the thioallyl complex then cleaves to give the butadienethiolate 257. The same product is also obtained by the reaction of the... 

Pinto, J.T., Qiao, C., Xing, J., Rivlin, R.S., Protomastro, M.L., Weissler, M.L., Tao, Y., Thaler, H. and Heston, W.D. (1997) Effects of garlic thioallyl derivatives on growth, glutathione concentration, and polyamine formation of human prostate carcinoma cells in culture. Am. J. Clin. Nutr. 66 398-405. 

Sigounas, G., Hooker, J.L., Li, W., Anagnostou, A. and Steiner, M. (1997b) S-allylmercapto-cysteine, a stable thioallyl compound, induces apoptosis in erythroleukemia cell lines. Nutr. Cancer. 28 153-159. 

The acid (BF3 Et20) catalyzed reaction of allene episulfide (127) has been reported to yield dimerization products, 1,4-dithiane (129), thioketone (130), and 1,3-dithiolane (131) (Scheme 49) <83JA6151>. The formation of these products might be interpreted in terms of intermediacy of the thioallyl ion (128), which undergoes cycloadditions with either (127) or (128) to give (129) and (130). In the case of (131), thioallyl (128) undergoes a 1,4-hydrogen shift prior to cycloaddition with (127) or (128) (Scheme 49). 

Intramolecular stepwise transfer of two hydrides to the bound thiophene leads to a thioallyl intennediate (B), characterized by NMR spectroscopy, in which the sulfur-containing ligand itself has come to formally occupy three coordination sites, this is of interest if a similar mechanism were to be invoked for a heterogeneous catalyst, since then a highly unsaturated site (3 CUS) would be required, assuming that hydrogen activation takes place elsewhere, or has taken place previously at the same site. 

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