Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes

Karl J Hale; Hamish A Watson; Soraya Manaviazar; Hannah G Steeds

Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes

Karl J Hale, Hamish A Watson, Soraya Manaviazar, Hannah G Steeds

School of Chemistry and Chemical Engineering

Research output: Other contribution

11 Citations (Scopus)

Abstract

O-Directed hydrostannation of β-cyclopropyl propargyl alcohol 22 with stannanes and cat. Et₃B in THF/H₂O or PhMe/MeOH fails to deliver any detectable products of α-stannylvinyl cation capture. Instead only α-stannyl-β-cyclopropylvinyl radical intermediates can be detected, which undergo fast H-atom abstraction and/or cyclopropane ring-opening as a result of eliminative β-scission.

Original language	English
Type	Preprint
Media of output	ChemRxiv Database
Number of pages	4
Publication status	Published - 15 Jul 2019

Publication series

Name	ChemRxiv
Publisher	American Chemical Society

Keywords

Stannylvinyl Cation
O-Directed Free Radical Hydrostannation with Ph3SnH/cat. Et3B, Propargylically-Oxygenated Alkyl Acetylenes, Stannylvinyl Radical, b-Stannylvinyl cation, Vinylperoxy radical, Trisubstituted Stannylvinyl Radical H-Atom Abstraction, Vinylstannane isomerisation, Allylic 1,3-strain and 1,2-strain, Internal Ligand Enhanced Radicalophilicity, Ph3Sn radicals have higher electron affinity, The magnitudes of polar solvent rate accelerations observed for genuinely ionic reaction mechanisms

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https://chemrxiv.org/articles/Fast_Ring-Opening_of_an_Intermediary_-Stannyl-_-Cyclopropylvinyl_Radical_Does_Not_Support_Formation_of_an_-Stannylvinyl_Cation_in_the_O-Directed_Free_Radical_Hydrostannation_of_Dialkyl_Acetylenes/8867651Licence: CC BY-NC

Further investigations into the mechanism of the o-directed free radical hydrostannation of alkyl and aryl acetylenes
Watson, H. (Author), Stevenson, P. (Supervisor) & Hale, K. (Supervisor), Jul 2022
Student thesis: Doctoral Thesis › Doctor of Philosophy

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Hale, K. J., Watson, H. A., Manaviazar, S., & Steeds, H. G. (2019, Jul 15). Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes. https://chemrxiv.org/articles/Fast_Ring-Opening_of_an_Intermediary_-Stannyl-_-Cyclopropylvinyl_Radical_Does_Not_Support_Formation_of_an_-Stannylvinyl_Cation_in_the_O-Directed_Free_Radical_Hydrostannation_of_Dialkyl_Acetylenes/8867651

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title = "Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes",

abstract = "O-Directed hydrostannation of β-cyclopropyl propargyl alcohol 22 with stannanes and cat. Et3B in THF/H2O or PhMe/MeOH fails to deliver any detectable products of α-stannylvinyl cation capture. Instead only α-stannyl-β-cyclopropylvinyl radical intermediates can be detected, which undergo fast H-atom abstraction and/or cyclopropane ring-opening as a result of eliminative β-scission.",

keywords = "Stannylvinyl Cation, O-Directed Free Radical Hydrostannation with Ph3SnH/cat. Et3B, Propargylically-Oxygenated Alkyl Acetylenes, Stannylvinyl Radical, b-Stannylvinyl cation, Vinylperoxy radical, Trisubstituted Stannylvinyl Radical H-Atom Abstraction, Vinylstannane isomerisation, Allylic 1,3-strain and 1,2-strain, Internal Ligand Enhanced Radicalophilicity, Ph3Sn radicals have higher electron affinity, The magnitudes of polar solvent rate accelerations observed for genuinely ionic reaction mechanisms",

author = "Hale, {Karl J} and Watson, {Hamish A} and Soraya Manaviazar and Steeds, {Hannah G}",

year = "2019",

month = jul,

day = "15",

language = "English",

series = "ChemRxiv",

publisher = "American Chemical Society",

type = "Other",

}

Hale, KJ, Watson, HA, Manaviazar, S & Steeds, HG 2019, Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes.. <https://chemrxiv.org/articles/Fast_Ring-Opening_of_an_Intermediary_-Stannyl-_-Cyclopropylvinyl_Radical_Does_Not_Support_Formation_of_an_-Stannylvinyl_Cation_in_the_O-Directed_Free_Radical_Hydrostannation_of_Dialkyl_Acetylenes/8867651>

TY - GEN

T1 - Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes

AU - Hale, Karl J

AU - Watson, Hamish A

AU - Manaviazar, Soraya

AU - Steeds, Hannah G

PY - 2019/7/15

Y1 - 2019/7/15

N2 - O-Directed hydrostannation of β-cyclopropyl propargyl alcohol 22 with stannanes and cat. Et3B in THF/H2O or PhMe/MeOH fails to deliver any detectable products of α-stannylvinyl cation capture. Instead only α-stannyl-β-cyclopropylvinyl radical intermediates can be detected, which undergo fast H-atom abstraction and/or cyclopropane ring-opening as a result of eliminative β-scission.

AB - O-Directed hydrostannation of β-cyclopropyl propargyl alcohol 22 with stannanes and cat. Et3B in THF/H2O or PhMe/MeOH fails to deliver any detectable products of α-stannylvinyl cation capture. Instead only α-stannyl-β-cyclopropylvinyl radical intermediates can be detected, which undergo fast H-atom abstraction and/or cyclopropane ring-opening as a result of eliminative β-scission.

KW - Stannylvinyl Cation

KW - O-Directed Free Radical Hydrostannation with Ph3SnH/cat. Et3B, Propargylically-Oxygenated Alkyl Acetylenes, Stannylvinyl Radical, b-Stannylvinyl cation, Vinylperoxy radical, Trisubstituted Stannylvinyl Radical H-Atom Abstraction, Vinylstannane isomerisati

M3 - Other contribution

T3 - ChemRxiv

ER -

Fast Ring-Opening of an Intermediary α-Stannyl-β-Cyclopropylvinyl Radical Does Not Support Formation of an α-Stannylvinyl Cation in the O-Directed Free Radical Hydrostannation of Dialkyl Acetylenes

Abstract

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Student theses

Further investigations into the mechanism of the o-directed free radical hydrostannation of alkyl and aryl acetylenes

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