Selenoether compounds

The structural parameters describing the geometry of di-/inter-halogens binding to chalcogen-containing molecules (thioethers, selenoethers, thiocar-bonyl, and selenocarbonyl compounds) are defined in Figure 1. 

Reactions of organomagnesium compounds with thioethers usually take other pathways, and uncatalysed reactions involving displacement of thiolate are rare. On the other hand, several examples of nickel(n)-catalysed reactions have been described, and analogous reactions of selenoethers have also been reported, e.g. 

Scheme 5-32 shows a series of ferrocenyl compounds that can be formally considered as derivatives of the ferrocenyl chalcogenols, Fc-EH (E = O, S, Se, Te), including ferrocenyl ethers, thioethers, selenoethers and telluroethers. The analogous l,T-ferrocenediyl compounds, formally derived from fc(EH)2 (E = O, S, Se, Te), are presented in Scheme 5-33 (see Appendix). 

While unsubstituted or monosubstituted 1,2,5-selenadiazoles are reportedly quite stable to aqueous or alcoholic hydroxide solutions, the disubstituted derivatives (201) react quite readily even at — 70° with Grignard reagents or alkyl lithiums. The reaction is believed to proceed through a selenoether intermediate (202) to give 1,2-dicarbonyl compounds (203) ° [Eq.(49)]. 

The chemistry of organoselenium and organotellurium compounds Recent developments in the coordination chemistry of selenoether and telluroether ligands ... 

Table 5.20 - Selenium bases selenides (selenoethers), selenocarbonyl and selenophos-phoryl compounds.

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