Hypervalent silicon hydrides: evidence of their intermediacy in the reaction of optically active 1-NpPhMeSiH(D) with hydrides

Brefort, J.L.; Corriu, Robert J. P.; Guérin, Christian; Henner, B.

doi:10.1016/0022-328x(89)87270-5

Cited by 34 publications

(7 citation statements)

References 7 publications

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“…Deprotonation and generation of silyl lithium reagents have been achieved using strong bases like tert -butyl lithium and lithium diisopropylamide, but only for the special cases of dihydridodisilylsilanes . Reduction to give silyl potassium reagents has been achieved with sodium/potassium alloys or potassium hydride . The reaction of arylhydridosilanes with lithium metal has only been mentioned briefly in the literature, but is noted to lead to an number of side reactions including disilane formation and disproportionation, and is thus considered unsuitable for the formation of silyl lithium reagents. ,, To the best of our knowledge, silyl lithium reagents generated from hydridosilanes and lithium metal have not been applied in the synthesis of functionalized silanes.…”

Section: Resultsmentioning

confidence: 99%

Sequential C−Si Bond Formations from Diphenylsilane: Application to Silanediol Peptide Isostere Precursors

Nielsen

Skrydstrup

2008

J. Am. Chem. Soc.

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The report of silanediol peptide isosteres as highly active inhibitors of proteolytic enzymes has triggered an increased interest for these compounds, thereby necessitating a general and direct synthetic access to this unusual class of protease inhibitors. In this paper, we report on the two-step assembly of the carbon-silicon backbone of a silane-containing dipeptide fragment. The synthetic scheme is comprised of an alkene hydrosilylation step with the simple precursor, diphenylsilane, using either a radical initiator or RhCl(PPh3)3, Wilkinson's catalyst, for the creation of a hydridosilane and the first new carbon-silicon bond. The next step is the reduction of this hydridosilane with lithium metal providing a silyl lithium reagent, which undergoes a highly diastereoselective addition to an optically active tert-butanesulfinimine, thus generating the second C-Si bond. This method allows sequential functionalization of the two hydrides in diphenylsilane by chemoselective discrimination.

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Section: Resultsmentioning

confidence: 99%

Sequential C−Si Bond Formations from Diphenylsilane: Application to Silanediol Peptide Isostere Precursors

Nielsen

Skrydstrup

2008

J. Am. Chem. Soc.

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“…It is generally accepted that the formation of the hydride (1) proceeds through anionic hypervalent intermediates with a five coordinate Si center (eqn (2)). 32 In general, the in situ prepared alkali metal hydride species precipitate from solution in their cubic crystal lattices. However, these remaining suspensions are extremely finely dispersed and highly reactive (the presence of nanoparticles should not be excluded, vide infra).…”

Section: Group 1 Metal Hydride Complexesmentioning

confidence: 99%

Molecular early main group metal hydrides: synthetic challenge, structures and applications

2012

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Within the general area of early main group metal chemistry, the controlled synthesis of well-defined metal hydride complexes is a rapidly developing research field. As group 1 and 2 metal complexes are generally highly dynamic and lattice energies for their [MH](∞) and [MH(2)](∞) salts are high, the synthesis of well-defined soluble hydride complexes is an obvious challenge. Access to molecular early main group metal hydrides, however, is rewarding: these hydrocarbon-soluble metal hydrides are highly reactive, have found use in early main group metal catalysis and are potentially also valuable molecular model systems for polar metal hydrides as a hydrogen storage material. The article focusses specifically on alkali and alkaline-earth metal hydride complexes and discusses the synthetic challenge, molecular structures, reactivity and applications.

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“…42 If the proposed mechanism involving hydride exchange is correct, the reaction of KH and Ph 3 SiH in the presence of 18crown-6 should produce 1, although difficulties have been noted previously with this procedure. 40 The reaction was attempted in an NMR tube, using 1.25 to 1.5 equivalents of hydride with respect to the silane and crown ether, and was followed by 1 H NMR spectroscopy at various time intervals (see ESI Fig. S6 ¶).…”

Section: Dynamic Nmr Spectroscopic Studiesmentioning

confidence: 99%

Hypervalent hydridosilicates: synthesis, structure and hydride bridging

et al. 2008

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A range of hydridosilicate anions has been prepared and characterised by spectroscopic, structural and computational methods. The general approach involved reaction of KH with a neutral silane precursor in the presence of [18]crown-6. In this manner, [K([18]crown-6)]+ salts of [Ph3SiH2](-) (1), [Ph3SiF2](-) (9), and [(p-FC6H4)3SiHF](-)/[(p-FC6H4)3SiH2](-) (12) were stabilised and characterized by NMR spectroscopy and X-ray diffraction. In each case, the anion adopts a trigonal bipyramidal (TBP) geometry with three equatorial phenyl groups eclipsing the axial Si-H/Si-F bonds. The Si-H[dot dot dot]K distances, along with DFT calculations on 1, indicate an electrostatic interaction that does not dictate the geometry adopted by the anion. A [H2SiOiPr3](-) salt (7) has also been crystallised in the same way; X-ray diffraction shows in this case a distorted TBP array with axial hydride ligands, and both Si-H[...]K and Si-O[...]K interactions. 1H NMR exchange experiments show 1 to undergo facile hydride exchange with Ph3SiH. Compound 1 acts as a good hydride transfer reagent to a variety of substrates, but its high reactivity often results in redistribution and other side reactions.

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Hypervalent silicon hydrides: evidence of their intermediacy in the reaction of optically active 1-NpPhMeSiH(D) with hydrides

Cited by 34 publications

References 7 publications

Sequential C−Si Bond Formations from Diphenylsilane: Application to Silanediol Peptide Isostere Precursors

Sequential C−Si Bond Formations from Diphenylsilane: Application to Silanediol Peptide Isostere Precursors

Molecular early main group metal hydrides: synthetic challenge, structures and applications

Hypervalent hydridosilicates: synthesis, structure and hydride bridging

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