Synthese bei Temperaturen unter −80°C

Small differences in free enthalpies of activation (ΔΔG‡) between competing reactions give rise to high selectivity at low enough temperatures. Special techniques are necessary, in order to exploit this effect in preparative-scale conversions. An experimental set-up is described here with which rea...

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Main Authors: Dieter Seebach, August Hidber
Format: Article
Language:deu
Published: Swiss Chemical Society 1983-12-01
Series:CHIMIA
Online Access:https://www.chimia.ch/chimia/article/view/9600
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author Dieter Seebach
August Hidber
author_facet Dieter Seebach
August Hidber
author_sort Dieter Seebach
collection DOAJ
description Small differences in free enthalpies of activation (ΔΔG‡) between competing reactions give rise to high selectivity at low enough temperatures. Special techniques are necessary, in order to exploit this effect in preparative-scale conversions. An experimental set-up is described here with which reactions can conveniently be carried out in up to five liter flasks at temperatures down to -150°C. In one apparatus, the cooling bath is liquid, in another one the reaction vessel is cooled directly by evaporating liquid nitrogen. Applications described are brominations of C,C double bonds and reactions of lithium enolates with electrophiles.
format Article
id doaj-art-2c3db31068ee4fa1be4efd26e4d645a9
institution OA Journals
issn 0009-4293
2673-2424
language deu
publishDate 1983-12-01
publisher Swiss Chemical Society
record_format Article
series CHIMIA
spelling doaj-art-2c3db31068ee4fa1be4efd26e4d645a92025-08-20T02:29:52ZdeuSwiss Chemical SocietyCHIMIA0009-42932673-24241983-12-01371210.2533/chimia.1983.449Synthese bei Temperaturen unter −80°CDieter Seebach0August Hidber1Laboratorium für Organische Chemie der Eidgenössischen Technischen Hochschule, ETH-Zentrum, Universitätstrasse 16, CH-8092 ZürichLaboratorium für Organische Chemie der Eidgenössischen Technischen Hochschule, ETH-Zentrum, Universitätstrasse 16, CH-8092 Zürich Small differences in free enthalpies of activation (ΔΔG‡) between competing reactions give rise to high selectivity at low enough temperatures. Special techniques are necessary, in order to exploit this effect in preparative-scale conversions. An experimental set-up is described here with which reactions can conveniently be carried out in up to five liter flasks at temperatures down to -150°C. In one apparatus, the cooling bath is liquid, in another one the reaction vessel is cooled directly by evaporating liquid nitrogen. Applications described are brominations of C,C double bonds and reactions of lithium enolates with electrophiles. https://www.chimia.ch/chimia/article/view/9600
spellingShingle Dieter Seebach
August Hidber
Synthese bei Temperaturen unter −80°C
CHIMIA
title Synthese bei Temperaturen unter −80°C
title_full Synthese bei Temperaturen unter −80°C
title_fullStr Synthese bei Temperaturen unter −80°C
title_full_unstemmed Synthese bei Temperaturen unter −80°C
title_short Synthese bei Temperaturen unter −80°C
title_sort synthese bei temperaturen unter 80°c
url https://www.chimia.ch/chimia/article/view/9600
work_keys_str_mv AT dieterseebach synthesebeitemperaturenunter80c
AT augusthidber synthesebeitemperaturenunter80c