1,2‐Diboracyclopentanes without Strong Donor Substituents: Synthesis, Reactions, and Computational Analysis

Präsang, Carsten; Şahin, Yüksel; Hofmann, Matthias; Geiseler, Gertraud; Massa, Werner; Berndt, A.

doi:10.1002/ejic.200800622

Cited by 19 publications

(7 citation statements)

References 24 publications

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“…114 The synthesis, reactions and computational analysis of a series of 1,2-diboracyclopentanes have been described. 115 o-(Hydroxydimethylsilyl)(dimesitylboryl)benzene has been shown to undergo intramolecular cyclisation to yield the Si-O-B heterocycle, 5,5-dimesityl-2,2-dimethyl-3,4-benzo-1,2,5-oxasilaboracyclopentene which was characterized by X-ray crystallographic analysis and HF calculations. 116 Reaction of the diazaboroline system (21) with lithium diisopropylamide has been shown to result in the formation of the anionic diazaborolide system (22).…”

Section: Mono- Di-and Trialkyl/aryl Boranes Including Fluorinated Bor...mentioning

confidence: 99%

Boron

Johnson¹

2009

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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Section: Mono- Di-and Trialkyl/aryl Boranes Including Fluorinated Bor...mentioning

confidence: 99%

Boron

Johnson¹

2009

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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“…14 Fischer and Power 14 divided known compounds into two classes, neutral complexes of RE=E'R 2 (where E = group 13 element and E'= group 14 element) and monoanionic complexes [R 2 E=E'R 2 ] -. Of the neutral complexes (RE=E'R 2 ), known compounds only include formal boron double bonds with either carbon 19 (4) or silicon 20 (5, Figure 7). In both cases, the boron-carbon and boron-silicon double bonds were identified to be 10% shorter than their respective standard single bonds.…”

Section: Multiple Bonding Between Groups 13 and 14mentioning

confidence: 99%

“…In both cases, the boron-carbon and boron-silicon double bonds were identified to be 10% shorter than their respective standard single bonds. 19,20 In the case of the B-Si complex (5) computational studies identified that there was some resonance bonding with the ring nitrogen that also contributed to the bonding structure. 20 19,20 Examples of the monoanionic complexes ([R 2 E=E'R 2 ] -) are slightly more numerous, the most common type of compounds are boron-carbon complexes, where the boron is considered to be stabilising a carbanion.…”

Section: Multiple Bonding Between Groups 13 and 14mentioning

confidence: 99%

“…19,20 In the case of the B-Si complex (5) computational studies identified that there was some resonance bonding with the ring nitrogen that also contributed to the bonding structure. 20 19,20 Examples of the monoanionic complexes ([R 2 E=E'R 2 ] -) are slightly more numerous, the most common type of compounds are boron-carbon complexes, where the boron is considered to be stabilising a carbanion. 14 Recent work by Nakata et al 21,22 utilised a new synthetic approach (Scheme 2) to form complexes with multiple bonds between Ga-Si (6a), Ga-Ge (6b), In-Si (6c), and In-Ge (6d).…”

Section: Multiple Bonding Between Groups 13 and 14mentioning

confidence: 99%

“…Instead alkylidene compound (18) is formed, with the presence of toluene in the reaction mixture supporting α-elimination of a benzyl group. Heating the alkylidene complex (18) resulted in the formation of carbyne (19) and a second equivalent of toluene. 40 The neodymium trichloride salt was also reacted in this manner with benzyllithium to give a neodymium carbyne complex and two equivalents of toluene.…”

Section: Group 3 Carbenesmentioning

confidence: 99%

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The Synthesis of Novel Gallium Carbenes, Nitrenes, Phosphinidenes and Alkoxides

Cummins¹

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<p>In the present study, synthetic routes to formal double bonds between gallium and carbon (fig 1), nitrogen (fig 2), and phosphorus (fig 3) have been investigated. These synthetic routes utilised the monoanionic, four electron donor, β-diketiminate (BDI) ligand to provide both steric and electronic stabilisation to three coordinate gallium complexes. The known di-substituted β-diketiminatogallium complexes: [(BDI)GaMe₂] and [(BDI)Ga(NHPh)₂], as well the new complexes: [(BDI)GaBn₂], [(BDI)Ga(NHDMP)₂] (DMP = 2,6-Me₂C₆H₃), [(BDI)Ga(NHDIPP)₂] (DIPP = 2,6-iPr₂C₆H₃), [(BDI)Ga(PHPh)₂] were examined for their reactivity towards the α-proton elimination mechanism for the formation of multiple bonds that is observed in transition metals. All of these complexes were shown to be unreactive towards α-proton elimination. The di-substituted β-diketiminato-gallium complex [(BDI)GaMe₂] was subjected to various aniline derivatives to investigate if the methyl ligands exhibited the same reactivity as di-methyl transition metal complexes, where the methyl ligands could deprotonate the aniline to form a metal-imido complex. This complex was found to have no reactivity with anilines. The mono-substituted β-diketiminato-gallium complex [(BDI)Ga(NHDMP)Cl] was tested for its reactivity with ⁿBuLi to abstract the amide proton and eliminate LiCl to form a gallium imido complex. While the ¹H NMR spectrum of the reaction mixture showed that a reaction had occurred, the products could not be isolated for characterisation. Another mono-substituted β-diketiminato-gallium complex [(BDI)Ga(PHPh)Cl] was also tested for its reactivity with ⁿBuLi to abstract the phosphide proton and eliminate LiCl to form a gallium phosphinidene complex. The ¹H NMR spectrum and ³¹P NMR spectrum of the isolated complex revealed that it still contained a phosphide proton, however the gallium centre now appeared to be bonded to a former methine carbon of an isopropyl group of the BDI ligand (fig 32). This bond may have formed through metathesis between an intermediate containing a gallium-phosphorus double bond, and the C-H bond of the isopropyl group. Further mechanistic studies could confirm if an intermediate such as [fig 3] is formed, and the synthetic strategy altered to isolate it. The synthesis of β-diketiminato-gallium-alkoxide complexes was also attempted, however the products of these synthesises could not be isolated due to solubility issues, potentially due to polymerisation.</p>

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Borata‐Alkene Species as Nucleophilic Reservoir

2021

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α‐Monoboryl anions show remarkable stability due to the valence deficiency of the adjacent three‐coordinate boron center and can be expressed as its resonance form, the borata‐alkene systems [R2B=CH2]−. The diversity of synthetic approaches as well as the properties of the C=B bond are disclosed in this review, dealing with both electronic and structural properties of the boryl moieties involved. Full characterization in solid state by X‐ray diffraction demonstrated the short distances between B and C, as a consequence of the boron ylide character in the boron‐stabilized carbanions. This review includes a collection of C−B length distances as well as 11B NMR data that can be useful for diagnostic evidence of the partial boron‐carbon double‐bond character. Natural bond orbital (NBO) analysis on DFT computed structures also supports and justifies the borata‐alkene character. The reactivity of the C=B bond acting as nucleophilic synthon is unveiled through extensive electrophilic trapping examples. The homologation protocols with diborylmethane, via single carbon chain extension, involves a facile introduction of the C(sp3)−B bonds, which can be subsequently transformed into functionalized target products, containing C−O, C−N or C−C bonds.

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1,2‐Diboracyclopentanes without Strong Donor Substituents: Synthesis, Reactions, and Computational Analysis

Cited by 19 publications

References 24 publications

Boron

Boron

The Synthesis of Novel Gallium Carbenes, Nitrenes, Phosphinidenes and Alkoxides

Borata‐Alkene Species as Nucleophilic Reservoir

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