σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3

We have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3...

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Main Authors:	Alexander Bähr, Lewis C. Wilkins, Kevin Ollegott, Benson M. Kariuki, Rebecca L. Melen
Format:	Article
Language:	English
Published:	MDPI AG 2015-03-01
Series:	Molecules
Subjects:	boron trispentafluorophenyl borane B(C6F5)3 Lewis acid alkyne
Online Access:	http://www.mdpi.com/1420-3049/20/3/4530

id	doaj-20662d22d0e447c7aa8ca8f3dd7b86cc
record_format	Article
spelling	doaj-20662d22d0e447c7aa8ca8f3dd7b86cc2020-11-24T20:59:38ZengMDPI AGMolecules1420-30492015-03-012034530454710.3390/molecules20034530molecules20034530σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3Alexander Bähr0Lewis C. Wilkins1Kevin Ollegott2Benson M. Kariuki3Rebecca L. Melen4School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UKSchool of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UKSchool of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UKSchool of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UKSchool of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, Cymru/Wales, UKWe have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3 which proceed via 1,2-addition of the ester and B(C6F5)3 across the alkyne, the inclusion of an additional CH2 spacer switches off the intramolecular cyclization and selective σ-activation of the carbonyl group is observed through adduct formation. This change in reactivity appears due to the instability of the species which would be formed through B(C6F5)3 activation of the alkyne.http://www.mdpi.com/1420-3049/20/3/4530borontrispentafluorophenyl boraneB(C6F5)3Lewis acidalkyne
collection	DOAJ
language	English
format	Article
sources	DOAJ
author	Alexander Bähr Lewis C. Wilkins Kevin Ollegott Benson M. Kariuki Rebecca L. Melen
spellingShingle	Alexander Bähr Lewis C. Wilkins Kevin Ollegott Benson M. Kariuki Rebecca L. Melen σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3 Molecules boron trispentafluorophenyl borane B(C6F5)3 Lewis acid alkyne
author_facet	Alexander Bähr Lewis C. Wilkins Kevin Ollegott Benson M. Kariuki Rebecca L. Melen
author_sort	Alexander Bähr
title	σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3
title_short	σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3
title_full	σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3
title_fullStr	σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3
title_full_unstemmed	σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3
title_sort	σ- versus π-activation of alkynyl benzoates using b(c6f5)3
publisher	MDPI AG
series	Molecules
issn	1420-3049
publishDate	2015-03-01
description	We have prepared a range of alkynyl benzoates in high yields and have investigated their reactivities with the strong Lewis acid B(C6F5)3. In such molecules both σ-activation of the carbonyl and π-activation of the alkyne are possible. In contrast to the reactivity of propargyl esters with B(C6F5)3 which proceed via 1,2-addition of the ester and B(C6F5)3 across the alkyne, the inclusion of an additional CH2 spacer switches off the intramolecular cyclization and selective σ-activation of the carbonyl group is observed through adduct formation. This change in reactivity appears due to the instability of the species which would be formed through B(C6F5)3 activation of the alkyne.
topic	boron trispentafluorophenyl borane B(C6F5)3 Lewis acid alkyne
url	http://www.mdpi.com/1420-3049/20/3/4530
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σ- versus π-Activation of Alkynyl Benzoates Using B(C6F5)3

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