PDF herunterladen
Synthesis 1993; 1993(6): 606-610
DOI: 10.1055/s-1993-25911
paper
© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Synthesis of Sterically Congested Acetic Acid Derivatives: The Reaction of Hindered α-Oxo Esters with Pentasubstituted Aryl Grignard Reagents

A. F. Hegarty* , P. O'Neill
  • *Chemistry Department, University College Dublin, Dublin 4, Ireland
Weitere Informationen

Publikationsverlauf

Publikationsdatum:
17. September 2002 (online)

  als PDF herunterladen  Lizenzen und Reprints Alle Artikel dieser Rubrik

The reactions of pentamethylphenylmagnesium bromide and pentachlorophenylmagnesium chloride with tert-butyl 2-oxo-3,3-dimethylbutanoate to give the 2-aryl-2-hydroxy-3, 3-dimethylbutanoate esters were investigated. Attempted acid catalysed dealkylation of the tert-butyl 2-hydroxy-3,3-dimethyl-2-(pentamethylphenyl) butanoate to the corresponding acid was accompanied by skeletal rearrangement, while the corresponding pentachlorophenyl ester reacted normally. The corresponding α- pentachlorophenyl α-α-tert-butyl acetic acid 15 was synthesised without rearrangement. The reaction of pentachlorophenylmagnesium chloride with diisopropyl oxalate gave the α-oxo ester 18, which reacted with pentamethylphenylmagnesium bromide to afford the unsymmetrical diarylacetate ester 22. The corresponding acid chloride 25 could not be converted to the interesting unsymmetrical diarylketene 26.