Thiolates tris

Quite a number of asymmetric thiol conjugate addition reactions are known [84], but previous examples of enantioselective thiol conjugate additions were based on the activation of thiol nucleophiles by use of chiral base catalysts such as amino alcohols [85], the lithium thiolate complex of amino bisether [86], and a lanthanide tris(binaphthoxide) [87]. No examples have been reported for the enantioselective thiol conjugate additions through the activation of acceptors by the aid of chiral Lewis acid catalysts. We therefore focussed on the potential of J ,J -DBFOX/ Ph aqua complex catalysts as highly tolerant chiral Lewis acid catalyst in thiol conjugate addition reactions. 

Table 6.2 Selected bond angles and lengths of medicinal gold(l) thiolates and 2,4,6-tri/sopropylphenylthiolatogold(l) analogs. Adapted from Shaw [17],...

An S4 coordination sphere of the type seen in the Ada protein, where four cysteines coordinate, was achieved with the tridentate tris(2-mercapto-l-phenylimidazolyl)hydroborato ligand. The zinc thiophenolate derivative showed reactivity of the thiolate linkage (Figure 8).506... 

Cd thiolates and selenolates tend to form q-S- or q-Se-bridged dinuclear species, even with bulky organic groups, e.g., 2,4,6-tri-t-butylphenyl.317 318 With some ligand combinations, heterocubanes with Cd4S4 core or oligonuclear species derived from heterocubanes are formed.319,320... 

With simple Hg thiolates the structures of bis(ethanethiolato)mercury Hg(SEt)2321 and of the cysteamine complex [Hg S(CH2)2NH3 2]Cl2322 have reference character, as only weak or no secondary bonds are present, and therefore the central S—Hg—S entities can be considered to be unperturbed. In mercury bis(tri-t-butoxysilanethiolate) Hg[SSi(o-t-Bu)3], with a strictly linear S—Hg—S unit, two weak intramolecular O II g interactions obviously do not affect the bonding in this unit.323... 

The most effective synthetic control of the thiolation of bismuth has been achieved using reactions of bismuth chloride with aminothiolate salts (potassium) prepared in situ. Although the reactions are not quantitative, the molecular stoichiometry can be reliably selected and a systematic series of mono-, bis-, and tris-thiolates have been isolated and comprehensively characterized. (189). 

Fig. 17. Schematic drawing of a predicted hexameric ring structure for a 1 1 gold(I)-thiolate (417) and found in the crystal structure of Au(I)-2,4,6-tri(isopropyl)thi-ophenolate (418).

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