Synthesis of a highly enantiomerically enriched silyllithium compound

Strohmann, Carsten; Hörnig, Jan; Auer, Dominik

doi:10.1039/b111687h

Cited by 64 publications

(40 citation statements)

References 8 publications

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“…However, there is less information about the solid-state structures of these compounds compared to organolithium compounds, which is due to the limited synthetic pathways and the necessity of special starting materials. In general, their preparation is limited to the cleavage of silicon-silicon bonds in phenyl-substituted disilanes, [32,34] the transmetallation of certain metallosilanes [35] and the direct lithiation of silyl halides. [36] The following chapter deals with the most important solid-state structures of silyllithium compounds and their main differences to the related alkyllithium compounds.…”

Section: Structure Principles Of Silyllithium Compoundsmentioning

confidence: 99%

Structure Formation Principles and Reactivity of Organolithium Compounds

Gessner

Däschlein

Strohmann

2009

Chemistry A European J

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240

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The structure-reactivity relationship is an important feature of organolithium compounds. The knowledge of the structure of reactive species is crucial for the elucidation of reaction mechanisms and the understanding of observed selectivities. This concept article gives an overview over the structural principles of lithium organics and their Lewis base coordinated complexes in the solid state. The transition from the oligomeric parent structures to smaller adducts, such as dimers and monomers, as well as special degrees of aggregation is presented. Besides the commonly used alkyllithium compounds, a short overview over the structural principles of the higher homologous silyllithium compounds is given. Moreover, the structure-reactivity relationship is depicted by means of the reactivity of the Lewis bases towards intramolecular decomposition reactions with the organolithium compound. Selected examples confirm the importance of structure elucidation for the understanding of mechanistic pathways and selectivities.

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Section: Structure Principles Of Silyllithium Compoundsmentioning

confidence: 99%

Structure Formation Principles and Reactivity of Organolithium Compounds

Gessner

Däschlein

Strohmann

2009

Chemistry A European J

Self Cite

240

111

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“…[11][12][13] Subsequent trapping of the lithiated species with electrophiles such as chlorosilanes or alkyl halides results in the formation of novel stereochemically pure silicon-chiral compounds. However, the lithiosilanes involved can potentially lose stereo-information during the reaction process due to their relatively low configurative stabilities.…”

Section: Introductionmentioning

confidence: 99%

“…[10] For compounds with only one stereocenter (enantiomers), the formation of diastereomers by the addition of a chiral auxiliary has proved to be the method of choice. One recent example is the treatment of aminomethyl-functionalized silanes with mandelic acid, [11] which resulted in quaternization of the nitrogen in the side-arm of the molecule to form diastereomeric salts with different crystallization properties. However, although this method has generally proved to be highly efficient, it is severely limited as only a few systems with suitable crystallization behavior have as yet been identified.…”

Section: Introductionmentioning

confidence: 99%

Preparation of “Si‐Centered” Chiral Silanes by Direct α‐Lithiation of Methylsilanes

Däschlein

Gessner

Strohmann

2010

Chemistry A European J

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The direct alpha-lithiation of methyl-substituted silanes as an efficient method for the preparation and elaboration of Si-chiral compounds is reported. Deprotonation of chiral oligosilanes occurs selectively and with high yields at the methyl group of the stereogenic silicon center, even in the presence of multiple methylsilyl or methylgermyl substituents. Computational studies have confirmed this preference as a consequence of pre-coordination of the lithiating agent by the amino side-arm and repulsion effects in the corresponding transition state. This complexation is also obvious from X-ray structure analyses of the alpha-lithiated silanes, which exhibit intriguing structure formation patterns differing in the type of aggregation and the amount of alkyllithium used. An alternative route to Si-chiral compounds is also presented, which involves desymmetrization of dimethylsilanes mediated by a chiral side-arm. Structure analyses and computational studies have shown that the diastereoselectivity of this alpha-lithiation is influenced by the selectivity of the formation of the stereogenic nitrogen upon complexation of the alkyllithium.

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“…[9] However, these fundamental approaches are afflicted with an intrinsic shortcoming which complicates synthetic applications since (almost) equimolar amounts of another organometallic 2 and 4, respectively, are formed as by-products.…”

Section: Introductionmentioning

confidence: 99%

On the Mechanism of the Reductive Metallation of Asymmetrically Substituted Silyl Chlorides

2004

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An investigation of the stereochemical course of the reductive metallation of silyl chlorides with silicon-centred chirality has revealed two major events which are detrimental to stereoselection during silyl anion formation: (1) chloride-induced racemisation of silyl chlorides and (2) nonstereoselective formal dimerisation during metallation providing the corresponding disilane. In control experiments, the stereochemical course of these processes has been independently verified for the reductive metallation of the enantioenriched cyclic silyl chloride (SiS)-7a (R = H, er Ն 88:12). A screening of several related derivatives of (SiS)-7a led to the sterically encumbered silyl chloride (SiR)-7c (R = iPr, er Ն 94:6) which displays some unique features. This structural modification pre-

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Synthesis of a highly enantiomerically enriched silyllithium compound

Cited by 64 publications

References 8 publications

Structure Formation Principles and Reactivity of Organolithium Compounds

Structure Formation Principles and Reactivity of Organolithium Compounds

Preparation of “Si‐Centered” Chiral Silanes by Direct α‐Lithiation of Methylsilanes

On the Mechanism of the Reductive Metallation of Asymmetrically Substituted Silyl Chlorides

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