Base catalysed rearrangements involving ylide intermediates. Part 15. The mechanism of the Stevens [1,2] rearrangement

Ollis, W. D.; Rey, Max; Sutherland, I. O.

doi:10.1039/p19830001009

Cited by 107 publications

(46 citation statements)

References 12 publications

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“…1 A vexing trait of these reactions is that they are routinely plagued by competitive [1,2]-sigmatropic rearrangements (eq 1). 2 Concerted [1,2] rearrangements of this type are not viable in theoretical analyses, 3 and the understanding of [1,2] rearrangements has focused on stepwise mechanisms.…”

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confidence: 99%

Dynamics and a Unified Understanding of Competitive [2,3]- and [1,2]-Sigmatropic Rearrangements Based on a Study of Ammonium Ylides

2014

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The [2,3]- and [1,2]-sigmatropic rearrangements of ammonium ylides are studied by a combination of experimental, standard computational, and dynamic trajectory methods. The mixture of concerted [2,3] rearrangement and bond cleavage observed experimentally is accounted for by the outcome of trajectories passing through the formal [2,3] rearrangement transition state. In this way the bond cleavage is promoted by the pericyclic stabilization of the [2,3] transition state. It is proposed that this dynamic effect is responsible for the pervasive co-occurrence of the two rearrangements.

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mentioning

confidence: 99%

Dynamics and a Unified Understanding of Competitive [2,3]- and [1,2]-Sigmatropic Rearrangements Based on a Study of Ammonium Ylides

2014

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“…The most studied reaction of quaternary ammonium salts is the Hofmann degradation [21] which would give rise to benzyldimethylamine, hydrogen fluoride, and the corresponding alkene (Scheme 2). The evidence for the Hofmann elimination depends on the detection of the alkene.…”

Section: Resultsmentioning

confidence: 99%

A simultaneous TG-DTG-DSC-quadrupole mass spectrometric study

Prasad

Sudhakarbabu

Sreedhar

et al. 2014

J Therm Anal Calorim

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Mechanistic aspects of the thermal decomposition of benzyl-triethyl-ammonium tetrafluoroborate (BTEATFB) employing simultaneous TG-DSC coupled with a quadrupole mass spectrometer are considered in this work. The experiments were conducted in an inert atmosphere of helium. The decomposition of BTEATFB proceeds through several competing mechanisms. While nucleophilic substitution reaction occurs through the formation of a tertiary amine and plays an important role in the initial stages of the decomposition, and the probability of Hoffman elimination also exists.

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“…The chiral, cyclometallated, complex 4, and 5 were prepared according to Scheme 1 starting from readily available 43 The chiral imidazolium salts 6, 7 and 8 which were required for the preparation of the gold NHC complexes 11 and 12 were synthesised by the 'one-pot' procedures reported by Alexakis et al 45 and Hermann and co-workers (Scheme 2). 46 Hence, reaction of either (S)-(-)-α-methylbenzylamine or (S)-(-)-1-(1-naphthyl)ethylamine with glyoxal and paraformaldehyde in the presence of either HCl or HBF 4 at 40 °C in toluene overnight afforded the desired salts.…”

Section: Synthesis Of Chiral Gold Complexesmentioning

confidence: 99%

Some insights into the gold-catalysed A 3 -coupling reaction

Price

Brisdon

Randall

et al. 2017

Journal of Organometallic Chemistry

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Abstract.A series of cyclometallated and functionalised NHC gold(I) and gold(III) complexes, many of which feature chiral ligands, and their application to A 3 -coupling reactions is presented. Gold(III) complexes were found to be particularly effective catalysts for the coupling in a range of solvents, however no asymmetric induction was obtained when using chiral gold complexes and the rate of product formation was found to be similar even when using different ligand systems. In-situ NMR analysis of these reactions indicates that decomposition of the catalyst occurs during the course of the reaction while TEM studies revealed the presence of gold nanoparticles in crude reaction mixtures. Taken together these data suggest that the gold nanoparticales, rather than the intact gold complexes, could be the catalytically active species, and if so this may have significant implications for other gold-catalysed systems.Dedicated to Dr. Mark Whiteley (an outstanding colleague) on his retirement from the School of Chemistry, University of Manchester.

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Base catalysed rearrangements involving ylide intermediates. Part 15. The mechanism of the Stevens [1,2] rearrangement

Abstract: rearrangement of acyl-stabilised ammonium ylides has been investigated with regard to stereoselectivity, intramolecularity and the formation of products in addition to the [l ,Z] rearrangement 1012

Cited by 107 publications

References 12 publications

Dynamics and a Unified Understanding of Competitive [2,3]- and [1,2]-Sigmatropic Rearrangements Based on a Study of Ammonium Ylides

Dynamics and a Unified Understanding of Competitive [2,3]- and [1,2]-Sigmatropic Rearrangements Based on a Study of Ammonium Ylides

A simultaneous TG-DTG-DSC-quadrupole mass spectrometric study

Some insights into the gold-catalysed A 3 -coupling reaction

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