Selenide complexes, reactions synthesis

The synthetic utility of the vinylic sulfide and selenide approach is exemplified by the synthesis of enantio-pure (i )-(-)-ipsdienol, an insect aggregation pheromone (Sch. 13) [54], Kabat and Uskokovic have demonstrated the asymmetric catalytic synthesis of la,25-dihydroxyvitamin D3 (la,25(OH)2D3) A-ring synthon by means of a glyoxylate-ene reaction catalyzed by BINOL-Ti complex (1) (Sch. 14) [55]. 

Alkynyl(phenyl)iodonium salts have found synthetic application for the preparation of various substituted alkynes by the reaction with appropriate nucleophiles, such as enolate anions [980,981], selenide and telluride anions [982-984], dialkylphosphonate anions [985], benzotriazolate anion [986], imidazolate anion [987], N-functionalized amide anions [988-990] and transition metal complexes [991-993]. Scheme 3.291 shows several representative reactions the preparation of Ai-alkynyl carbamates 733 by alkynylation of carbamates 732 using alkynyliodonium triflates 731 [989], synthesis of ynamides 735 by the alkyny-lation/desilylation of tosylanilides 734 using trimethylsilylethynyl(phenyl)iodonium triflate [990] and the preparation of Ir(III) a-acetylide complex 737 by the alkynylation of Vaska s complex 736 [991]. 

In contrast to the synthetic accessibility of the above complexes using solution approaches, the synthesis of octahedral rhenium chalcogenide clusters requires the implementation of high temperature solid-state reactions, or the conversion of cluster-containing solids into soluble molecular species by the methods of cluster excision or dimensional reduction (see Section 7.2.2.1.8). While cluster excision has produced the mixed sulfide(selenide)-chloride clusters [Re6E4+ Clio 2 ] " ( = 1-3), the latter approach has led to the isolation of complexes with rhenium-chalcogenide cores [RegEgXg] - (E = S, Se X = C1, Br, I). 

In order to understand the growth of metal clusters in solution, one should start from a metal complex precursor, such as [My(CO)x], according to Eq. (1). The precursor can be generated in situ. The protocol synthesis of such a chemical precursor is represented by the flow-chart see Fig. 4 for the case of ruthenium-selenide. This flow chart summarizes the synthesis initially reported in 1991, " and it will be taken as the template for similar compounds. A careful follow-up of the reaction was made by means of the Indeed, following the synthesis without carbon, i.e., after step 3, a heteronuclear chemical precursor was identified Ru4Se2(CO)3(CO)g. The ongoing reaction under the boiling point of the solvent for 20 hours led to a complete pyrolysis of the heteronuclear molecular cluster compound to nanopowders of... 

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