The First Isolable 2‐Silenolate

Guliashvili, Tamaz; El‐Sayed, Ibrahim; Fischer, Andreas; Ottosson, Henrik

doi:10.1002/anie.200250400

Cited by 56 publications

(43 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 13 C shift of 268.3 ppm revealed a very deshielded central C atom, and the 29 Si shift of −64.5 ppm for the central Si atom indicated that is was very shielded. This 29 Si shift is similar to that of Kira's 4-silatriafulvene (−71.9 ppm [58]) and those of the silenolates prepared by Ohshita, Ishikawa, and Ottosson (−79 to −60 ppm [72,73]). …”

Section: -Silaallenessupporting

confidence: 71%

“…However, there is experimental evidence for a reduced dimerization aptitude of reverse polarized silenes. In the thermolytic formation of the transient 2-amino-2-siloxysilenes (75a-75c, Scheme 22) very little dimer formation was observed [8], and potassium silenolates revealed no tendency for dimerization [73]. Formation of dimers from lithium silenolates was suggested but not proven [72,121].…”

Section: Dimerization Aptitudementioning

confidence: 95%

“…11) [73]. Silenolate 33 had a SiC bond distance of 1.926Å, just slightly longer than a regular Si-C single bond, and the Si atom was markedly pyramidal ( α(Si) = 317.8 • ).…”

Section: Effects Of Substitution At Carbonmentioning

confidence: 98%

See 2 more Smart Citations

Silenes: Connectors between classical alkenes and nonclassical heavy alkenes

Ottosson

Eklöf

2008

Coordination Chemistry Reviews

Self Cite

137

View full text Add to dashboard Cite

Section: -Silaallenessupporting

confidence: 71%

Section: Dimerization Aptitudementioning

confidence: 95%

See 1 more Smart Citation

Silenes: Connectors between classical alkenes and nonclassical heavy alkenes

Ottosson

Eklöf

2008

Coordination Chemistry Reviews

Self Cite

137

View full text Add to dashboard Cite

“…[15] TheS i1ÀB1 bond in [2] À [1.859(2) ]i s similar in length to that in the neutral borasilene A [1.8379-(17) ]a nd considerably shorter than that in borasileneacetylide adduct A' ' [1.933 (3) ]. [16] TheB1 ÀCl1 bond in [2] À [1.879 (2) ]issignificantly longer than that in precursor 4 [1.7751 (17) ], which suggests that the electron donation from the chloride to the boron atom is weaker than in 4.T hese structural parameters show that the Si = Bb ond in [2] À exhibits double-bond character, with little contribution from as ilyl anion (R H 2 Si À ÀBMesCl) resonance structure. [16] TheB1 ÀCl1 bond in [2] À [1.879 (2) ]issignificantly longer than that in precursor 4 [1.7751 (17) ], which suggests that the electron donation from the chloride to the boron atom is weaker than in 4.T hese structural parameters show that the Si = Bb ond in [2] À exhibits double-bond character, with little contribution from as ilyl anion (R H 2 Si À ÀBMesCl) resonance structure.…”

mentioning

confidence: 99%

An Isolable Potassium Salt of a Borasilene–Chloride Adduct

et al. 2017

View full text Add to dashboard Cite

Among the variety of isolable compounds with multiple bonds involving silicon, examples of compounds that contain silicon-boron double bonds (borasilenes) still remain relatively rare.Herein, we report the synthesis of the potassium salt of ac hloride adduct of borasilene 1 ([2] À ), which was obtained as an orange crystalline solid. Single-crystal X-ray diffraction analysis and reactivity studies on [2] À confirmed the double-bond character of the Si = Bbond as well as the reduced Lewis acidity,w hich is due to the coordination of Cl À to the boron center.Athermal reaction of [2] À afforded ab icyclic product by formal intramolecular CÀHi nsertion across the Si=Bbond of 1,whichwas corroborated by atheoretical study.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

show abstract

“…Following the results described by Ottosson and coworkers for the generation of stable silenolates, [15] we reacted 2 with equimolar amounts of KO t Bu. As expected, the base was fully consumed for the abstraction of one SiMe 3 group to give monosilenolate 4.However, 4 was never isolated, even at low temperatures;instead, it reacted further in the proposed sila-aldol reaction.…”

mentioning

confidence: 99%

Synthesis of Structurally Complex Silicon Frameworks through the First Sila‐Aldol Reaction

et al. 2017

View full text Add to dashboard Cite

Herein, we report on the first sila-aldol reaction, which emphasizes the tight connection between silicon and carbon chemistry.T his novel synthetic method provides straightforwarda ccess to 2-oxahexasilabicyclo[3.2.1]octan-8ide,astructurally complex silicon framework, in quantitative yield. Its structure was confirmed by NMR spectroscopya nd X-ray crystallography,a nd it displays ad istinctive chargetransfer transition. The complete mechanism of this highly selective rearrangement cascade is outlined and supported by density functional theory (DFT) calculations,w hich highlight the thermodynamic driving force and the low activation barriers of this powerful silicon-carbon bond-forming strategy.The classical aldol reaction, and in particular its power in the reversible formation and cleavage of carbon-carbon bonds,is one of the most important biosynthetic tools for the evolution of life on earth. [1] On the basis of this general strategy,namely the merging of two carbonyl compounds,s ynthetic chemists have put al ot of emphasis on stereoselective aldol reactions over the last couple of centuries to accomplish results comparable to those achieved by organisms and enzymes in nature. [2][3][4][5] These synthetic approaches include,f or example, the use of organocatalysts (amine-based systems), [4,6] chiral auxiliaries (Evans oxazolidinone route), [7] as well as chiral Lewis acids (e.g., Zn, Ag, Pd, and Cu complexes) [4,5,8] and bases. [9] Forsilicon-based compounds,however, such siliconcarbon bond-forming reactions have not been reported, although they must be considered as ap owerful alternative to standard coupling techniques,s uch as the Wurtz reaction and related methods, [10] hydrosilylation, [11] as well as transition-metal-catalyzed silicon-carbon coupling reactions. [12] Consequently,w es et out to explore the applicability of the sila-aldol reaction as an ovel synthetic method for the synthesis of complex silicon-carbon frameworks.B ased on this sila-aldol strategy,w hich induced an anionic rearrangement cascade,w ea chieved the selective formation of 2-oxahexasilabicyclo[3.2.1]octan-8-ide 1 (Scheme 1).We considered the intramolecular sila-aldol reaction as an optimal starting point for the development of this trans-formation as it should be entropically favored and employs highly symmetric starting materials.H owever,t he synthesis and isolation of such compounds,f or example, a,w-bis-(acyl)silanes,were previously not possible.Given our ongoing interest in the formation of cyclic acylsilanes, [13] we were now able to accomplish the synthesis of 1,4-bis-(acyl)cyclohexasilane 2 by reacting 1,4-dipotassium-1,4-bis-(trimethylsilyl)cyclohexasilane (3) [14] with two equivalents of mesitoyl chloride (MesCOCl) in diethyl ether (Et 2 O) at À78 8 8C. This reaction resulted in the clean formation of airstable and crystalline 1,4-bis(mesitoyl)cyclohexasilane (2)a s a1 :1 mixture of the trans and cis isomers in 72 %y ield (Scheme 2), an optimal and highly promising precursor molecule for our subsequent studies.T he ...

show abstract

The First Isolable 2‐Silenolate

Cited by 56 publications

References 29 publications

Silenes: Connectors between classical alkenes and nonclassical heavy alkenes

Silenes: Connectors between classical alkenes and nonclassical heavy alkenes

An Isolable Potassium Salt of a Borasilene–Chloride Adduct

Synthesis of Structurally Complex Silicon Frameworks through the First Sila‐Aldol Reaction

Contact Info

Product

Resources

About