Silicon—manganese bonds

Triphenylphosphine reacts with the manganese-silicon bonded compound (6) by reductive elimination ... 

Silicon and germanium hydrides react with cobalt, manganese and rhenium carbonyls affording complexes having a silicon (or germanium)-metal bond. These reactions, described previously for inactive compounds have been used in the synthesis of optically active silyl and germyl-transition metals ... 

However, manganese hydrides undergo substitution at silicon without cleavage of the silicon-manganese bond Scheme 13) ... 

Despite the development of various intermolecular radical addition methods, those studies have rarely accommodated additional functionality, our discovery of the manganese-mediated photolysis conditions notwithstanding. Prior to that discovery, we began to elaborate an alternative strategy which employs temporary tethers ([115, 116] reviews of silicon-tethered reactions [117-120]) (silyl ether or acetal linkages) linking radical and acceptor. In this scenario the C-C bond is constructed via cyclization, in which internal conformational constraints can control diaster-eoselectivity. The tether itself would be converted to useful functionality upon cleavage, and once the tether is cleaved the net result may be considered as formal acyclic stereocontrol. ... 

Although even in the IiAUi cleavage of the Si-Pt bonds a reductive elimination process is likely to occur, since the configuration at silicon is almost completely retained, a nucleophilic displacement of the silyl ligand is still conceivable. Deuterium labeling experiments have unambiguously demonstrated this possibility in silyl-manganese complexes (213). 

The easy reductive elimination process does not seem to arise from a particular lability of hydrosilane adduct 166. Complex 166 is stable in solution. Moreover, functionalized silyl-manganese complexes were shown to undergo substitution at silicon without Si-Mn bond cleavage (251) (Scheme 58). 

As regards the similarity with simple coordination of two-electron ligands, it is of interest to discuss the oxidative addition of silicon hybrid to methyl cyclopentadienyl-manganese carbonyl and the nature of the bonding in the adduct. Hydrido silyl-manganese complexes were first prepared by Jetz and Graham according to... 

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