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Syntheses of β‐Lactones, 6. One‐Step Synthesis of β‐Lactones by Aldolization of Ketones or Aldehydes with 1‐Acylbenzotriazoles
Author(s) -
Wedler Christine,
Kleiner Katharina,
Kunath Annamarie,
Schick Hans
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960604
Subject(s) - chemistry , lithium diisopropylamide , cyclohexanone , deprotonation , lithium (medication) , amide , carboxamide , hydrogen atom , organic chemistry , lactone , medicinal chemistry , group (periodic table) , catalysis , ion , medicine , endocrinology
Abstract Benzotriazolides 1 of alkanoic acids with one hydrogen atom in α‐position to the carboxamide group can be deprotonated with lithium diisopropylamide or lithium hexamethyldisilazanide to amide enolates 2 which condense at −90 to −95°C with ketones or aldehydes 3 to afford benzotriazolides of O ‐lithiated β‐hydroxylalkanoic acids 4 . These reactive carboxamide derivatives cyclize with elimination of lithium benzotriazolide to the corresponding di‐ and trisubstituted β‐lactones. With regard to the formation of β‐monosubstituted β‐lactones from aldehydes the use of benzotriazolides as active carboxylic acid derivatives proved to be superior to the application of the corresponding phenyl esters. An α‐unsubstituted β‐lactone 6 was obtained from 1‐acetylbenzotriazole only with cyclohexanone. The other carbonyl compounds 3 did not provide the corresponding α‐unsubstituted β‐lactones 6 .