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Favorskii ‐Reaktion von enolisierbaren Cyclobutanonen: Abhängigkeit der Stereoselektivität von der Abgangsgruppe, der Temperatur und dem Lösungsmittel
Author(s) -
Martin Pierre
Publication year - 1983
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19830660421
Subject(s) - chemistry , stereoselectivity , solvent , leaving group , medicinal chemistry , base (topology) , stereochemistry , organic chemistry , catalysis , mathematical analysis , mathematics
Dependence of the Stereoselectivity on the Leaving Group, the Temperature and the Solvent in the Favorskii ‐Reaction of Enolisable Cyclobutanones The base‐induced contraction of enolisable 2‐halocyclobutanones is often not stereoselectiv. The cis / trans ‐isomer ratio in the cyclopropanecarboxylic acid 9 derived from 2,4‐ cis ‐substituted cyclobutanones 7 depends on the nature of the leaving group. In addition, the choice of the base, the temperature and the solvent can profoundly affect the stereoselectivity of the Favorskii ‐reaction. The use of the p ‐bromophenylsulphonyloxy group as leaving group and an inhomogenous reaction medium leads exclusively to cis ‐carboxylic acid 9 .