NMR Spectroscopic Observation of a Metal‐Free Acetylide Anion

Tanaka, Yoshiyuki; Arakawa, Makoto; Yamaguchi, Y.; Hori, Chieko; Ueno, Masahiro; Tanaka, Takeyuki; Imahori, Tatsushi; Kondo, Yoshinori

doi:10.1002/asia.200600099

Cited by 14 publications

(4 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the 13 C NMR shift of C ipso provides information on the ion association of the compound in solution (recently shown for a phenylacetylide anion in conjunction with a very bulky phosphazene base) [26] we are unable to speculate about the solution structure of the target compounds.…”

Section: Resultsmentioning

confidence: 99%

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline‐Earth‐Metal Acetylides

Guino-o

Alexander

McKee

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

The synthesis, structural, and spectral characterization as well as a theoretical study of a family of alkaline-earth-metal acetylides provides insights into synthetic access and the structural and bonding characteristics of this group of highly reactive compounds. Based on our earlier communication that reported unusual geometry for a family of triphenylsilyl-substituted alkaline-earth-metal acetylides, we herein present our studies on an expanded family of target derivatives, providing experimental and theoretical data to offer new insights into the intensively debated theme of structural chemistry in heavy alkaline-earth-metal chemistry.

show abstract

Section: Resultsmentioning

confidence: 99%

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline‐Earth‐Metal Acetylides

Guino-o

Alexander

McKee

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…Lithium acetylide products were characterized by 13 C NMR spectroscopy: 4a , 4b , and 4c are dimeric in 1:3 THF/Me 2 O, 5c,d and 4d is monomeric, with a 1:1:1:1 quartet for the C−Li carbon from coupling to one 7 Li 8a. This is the first reported characterization by NMR of a monomeric lithium acetylide. 5d, …”

Section: Referencesmentioning

confidence: 88%

Reactivity of Individual Organolithium Aggregates: A RINMR Study of n-Butyllithium and 2-Methoxy-6-(methoxymethyl)phenyllithium

et al. 2007

View full text Add to dashboard Cite

Low-temperature rapid injection NMR (RINMR) experiments were performed on two lithium reagents, n-butyllithium and 2-methoxy-6-(methoxymethyl)phenyllithium (5), with the goal of measuring the relative reactivity of the different aggregates (dimer, mixed dimer, and tetramer for n-BuLi, monomer and tetramer for 5) toward typical electrophiles. The reaction of the n-BuLi dimer with (trimethylsilyl)acetylene first forms the mixed dimer n-BuLi·Me3SiC⋮CLi, which is about 1/60 as reactive as the n-BuLi homodimer. The tetramer does not react. In the deprotonation of (phenylthio)acetylene, the n-BuLi dimer was found to be 3.5 × 108 as reactive as the tetramer, and in the addition to p-diethylaminobenzaldehyde, the relative reactivity was at least 2 × 104. In the deprotonation of (p-tolylsulfonyl)acetylene, the monomer of 5 was at least 1014 times as reactive as the tetramer. These measurements show that the difference in reactivity between the lower and higher aggregates of organolithium reagents can be many orders of magnitude higher than all previous estimates.

show abstract

“…This computational prediction is consistent with the experimental reaction rate being first order in all three reaction components (Figure ). Furthermore, we observed evidence for the weak coordination or partial deprotonation of 1h by P 1 – t Bu ( pre-TS-1 , Figure , also see Page S35 in the Supporting Information for NMR spectra), which is consistent with our proposal for TS-1 .…”

Section: Resultsmentioning

confidence: 99%

Organosuperbase-Catalyzed 1,1-Diboration of Alkynes

et al. 2022

View full text Add to dashboard Cite

1,1-Diboryl alkenes are versatile building blocks in organic synthesis and medicinal chemistry. However, there have been only a small number of established methods to prepare this class of compounds, and most of them used transition-metal catalysts, which are undesirable in the preparation of biologically relevant compounds. Herein, we report an unprecedented application of P1– t Bu phosphazene as a superbasic organocatalyst to promote 1,1-diboration reactions of unactivated aromatic and electron-deficient terminal alkynes. The dual Brønsted and Lewis basicity of this phosphazene enables the activation of reaction substrates and allows for high regio- and stereoselectivity to be obtained. A combination of thorough experimental and computational studies suggests interesting mechanistic insights for these phosphazene-catalyzed diboration reactions, which are also discussed in detail.

show abstract

NMR Spectroscopic Observation of a Metal‐Free Acetylide Anion

Cited by 14 publications

References 37 publications

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline‐Earth‐Metal Acetylides

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline‐Earth‐Metal Acetylides

Reactivity of Individual Organolithium Aggregates: A RINMR Study of n-Butyllithium and 2-Methoxy-6-(methoxymethyl)phenyllithium

Organosuperbase-Catalyzed 1,1-Diboration of Alkynes

Contact Info

Product

Resources

About