[1-(Trimethylsiloxy)alkyl]triphenylphosphonium Salts: Syntheses and Utilization. Comparisons with Analogous Pyridinium Salts

Anders, Ernst; Hertlein, Karola; Stankowiak, Achim; Irmer, Erhard

doi:10.1055/s-1992-26168

Cited by 16 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the 13 C{ 1 H} NMR spectrum of 7a or 7b , a doublet signal assignable to the PPh 3 -introduced carbon was observed at 82.9 ( 1 J PC = 64.8 Hz) or 82.1 ( 1 J PC = 66.2 Hz) ppm, respectively. These chemical shifts and coupling constants are comparable to those observed for [RCH(OSiMe 3 )PPh 3 ] + (R = H, Et, Ph, and 4-MeC 6 H 4 , 58−74 ppm, 1 J PC = 62−70 Hz) . The 29 Si{ 1 H} NMR spectrum of 7a or 7b also showed a doublet signal at 61.1 ( 3 J PSi = 10.8) or 76.5 ( 3 J PSi = 7.3) ppm, respectively.…”

Section: Resultssupporting

confidence: 79%

Hydrosilylation of Carbonyl Compounds with Hydrosilyliron Complexes Catalyzed by Cationic Silyleneiron Complexes

et al. 2010

View full text Add to dashboard Cite

A hydride abstraction from the hydrosilyliron complexes Cp(OC)2FeSiR2H (Cp = η5-C5H5, R = p-tolyl (1a), Me (1b)) in CD3CN afforded cationic silyleneiron complexes [Cp(OC)2FeSiR2(NCCD3)][B(Arf)4] (Arf = 3,5-bis(trifluoromethyl)phenyl, R = p-tolyl (2a), Me (2b)). The cationic silylene complexes 2 catalyzed hydrosilylation of aldehydes and ketones with 1 to give the corresponding alkoxysilyliron complexes 3−5 in moderate to high yield.

show abstract

Section: Resultssupporting

confidence: 79%

Hydrosilylation of Carbonyl Compounds with Hydrosilyliron Complexes Catalyzed by Cationic Silyleneiron Complexes

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Compound 16 has not yet been synthesized. However, we have a large body of synthetic data for nucleophilic substitution reactions with derivatives of 17 (synthesized from aliphatic and aromatic aldehydes, pyridine, and trimethylsilyl triflate). All of these results reveal that the exclusive preference of pathway b is the most important property of 17 (and presumably of 16 as well).…”

Section: Resultsmentioning

confidence: 99%

Preparation and Conversion of N-Halomethylpyridinium Halides. Comparison with Related Compounds

et al. 1999

Self Cite

View full text Add to dashboard Cite

N-Halomethylpyridinium halides 1a-f (X-CH(2)Py(+)X(-), X = Cl, Br) have been synthesized from a three-component reaction mixture containing a thionyl halide 5, formaldehyde (6), and a pyridine 7. The salts 1a-f react readily with a variety of heterocyclic nucleophiles to yield (in general, nonsymmetrical) 1,1-bis(heteroarylium)methyl salts 2ea-hb, (pathway a). The use of trichloroacetaldehyde (9) instead of formaldehyde in this three-component reaction leads to a salt 10 in which one of the CH(2)-hydrogens was replaced by the electron-withdrawing CCl(3) substituent. This changes the standard reaction pathway a of 1 in solution toward nucleophiles completely: the chlorinated N-vinylpyridinium salts 11 and 12 were formed after the reaction of 10 with pyridine or triphenylphosphane. These are useful intermediates for the synthesis of new N- and 4-substituted 1,4-dihydropyridines 13-15 as could be demonstrated for compound 11. To explain the reactivity pattern of compounds 1 and 10 and the related structures (MeO-CH(2)Py(+), 16, and Me(3)SiO-CH(2)Py(+), 17) we calculated, using ab initio and DFT methods, reaction pathways a and b, both in the gas phase and in solution using ammonia as a model nucleophile. For all of these compounds, pyridine displacement (pathway b) dominates in the gas phase. As an example the energy gap between these two transition states for 1a turns out to be relatively small (11.6 kcal/mol in favor of pathway b, TS2). Solvation effects can therefore stabilize the corresponding transition state TS1 more effectively. In a MeCN solution, TS1 is 1.6 kcal/mol less energetic than TS2.

show abstract

“…Activation of aldehydes can easily be followed via 1 H NMR spectroscopy through the loss of the characteristic aldehyde hydrogen signal. Especially, para ‐methylbenzaldehyde turned out to be ideally suited [32–35] . Its bonding to an FLP leads to a characteristic upfield shift of the chemical shift value for the methyl group in the 1 H NMR spectra.…”

Section: Resultsmentioning

confidence: 99%

“…To test the possible FLP‐like chemistry, we used the reaction with para ‐methylbenzaldehyde, since stoichiometric reactions with aldehydes were drawn on frequently to probe the FLP properties. [ 31 , 32 , 33 , 34 , 35 ] Activation of aldehydes can easily be followed via 1 H NMR spectroscopy through the loss of the characteristic aldehyde hydrogen signal. Especially, para ‐methylbenzaldehyde turned out to be ideally suited.…”

Section: Resultsmentioning

confidence: 99%

Directed Synthesis and Chemistry of Unsymmetric Dicationic Diboranes and Their Use in Frustrated Lewis Pair‐like Chemistry

Kistner

Kowatsch

März

et al. 2022

Chemistry A European J

View full text Add to dashboard Cite

The chemistry of dicationic diboranes with two BII atoms that are engaged in direct B−B bonding is by enlarge unexplored, although these molecules have intriguing properties due to their combined Lewis acidic and electron‐donor properties. Unsymmetric dicationic diboranes are extremely rare, but especially attractive due to their polarized B−B bond. In this work we report the directed synthesis of several stable unsymmetric dicationic diboranes by reaction between the electron‐rich ditriflato‐diborane B2(hpp)2(OTf)2 (hpp=1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐α]pyrimidinate) and phosphino‐pyridines, establishing B−N and B−P bonds with the diborane concomitant with triflate elimination. In the case of 2‐((ditertbutylphosphino)methyl)pyridine, the B−N bond is formed instantly, but the B−P bond formation requires (due to steric constraints) several days at ambient conditions for completion, creating an intermediate that could be used for frustrated Lewis pair (FLP)‐like chemistry. Here we test its reaction with an aldehyde, and propose a new type of FLP‐like chemistry.

show abstract

[1-(Trimethylsiloxy)alkyl]triphenylphosphonium Salts: Syntheses and Utilization. Comparisons with Analogous Pyridinium Salts

Cited by 16 publications

References 0 publications

Hydrosilylation of Carbonyl Compounds with Hydrosilyliron Complexes Catalyzed by Cationic Silyleneiron Complexes

Hydrosilylation of Carbonyl Compounds with Hydrosilyliron Complexes Catalyzed by Cationic Silyleneiron Complexes

Preparation and Conversion of N-Halomethylpyridinium Halides. Comparison with Related Compounds

Directed Synthesis and Chemistry of Unsymmetric Dicationic Diboranes and Their Use in Frustrated Lewis Pair‐like Chemistry

Contact Info

Product

Resources

About