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Säure‐Additionen an ‘Push‐Pull’‐Enine. Erste Beobachtung einer Umlagerung von 5‐Chloro‐5‐(dialkylamino)pentadienalen
Author(s) -
Berger Daniel,
Neuenschwander Markus
Publication year - 1996
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.19960790119
Subject(s) - chemistry , iminium , medicinal chemistry , stereochemistry , organic chemistry , catalysis
Reaction of ‘Push‐Pull’ Enynes with Acids. First Observation of a Rearrangement of 5‐Chloro‐5‐(dialkylamino)pentadienals ‘Push‐pull’‐enynes 7 react easily with HCl as well as with AcOH to give 5‐amino‐5‐chloropentadienals 8 and 5‐(acetoxy)‐5‐aminopentadienals 13 as well as the corresponding ketones. In view of a postulated rearrangement of compounds 8 and 13 ( Scheme 2 ), both types of compounds have been treated with traces of acid. While no definite reaction is observed in case of 13 , HCl‐addition products 8 easily and quantitatively rearrange to give 2 H ‐pyran‐2‐iminium chlorides 10 which are the postulated intermediates of the rearrangement 8 → 12 ( Scheme 2 ).