Reactions with Mercury Silyl Compounds

Some applications of the use of substituted disilyl mercury compounds, Hg(SiXa)2 (X = Me,Cl), are shown in Ikble III there is an early review article (421). In most cases, the mercury compound reacts with a metal-halogen bond to give a silicon halide and mercury as byproduct, e.g. (entry 1), 

Reactions of Silyl Alkali Metal Compounds with Metal Halides 

Entry derivative/solvent Metal halide Product Ref. 

Entry Mercurial Metal compound Silicon-metal product Ref. 

6 Hg(SiMe3 i cis-(Et3P)iPtCli Irans-(Me i)PtCl(PEt3)i (196) 

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Perlmutter used an oxymercuration/demercuration of a y-hydroxy alkene as the key transformation in an enantioselective synthesis of the C(8 ) epimeric smaller fragment of lb (and many more pamamycin homologs cf. Fig. 1) [36]. Preparation of substrate 164 for the crucial cyclization event commenced with silylation and reduction of hydroxy ester 158 (85-89% ee) [37] to give aldehyde 159, which was converted to alkenal 162 by (Z)-selective olefination with ylide 160 (dr=89 l 1) and another diisobutylaluminum hydride reduction (Scheme 22). An Oppolzer aldol reaction with boron enolate 163 then provided 164 as the major product. Upon successive treatment of 164 with mercury(II) acetate and sodium chloride, organomercurial compound 165 and a second minor diastereomer (dr=6 l) were formed, which could be easily separated. Reductive demercuration, hydrolytic cleavage of the chiral auxiliary, methyl ester formation, and desilylation eventually led to 166, the C(8 ) epimer of the... 

As an alternative to condensation of dichlorosilanes by alkali metals, it is possible to synthesize poly silanes by the reaction of preformed dilithio compounds with dichlorosilanes. An early synthesis of a copolymer by this route is illustrated in equation (19).10 (see also Section 5.9.2). Finally, poly(phenylmethylsilylene) has been made by thermal decomposition of a silyl-mercury polymer36 (equation (20)). 

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