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B ECKMANN ‐Umlagerung und Fragmentierung; V. Teil Mechanismus der 7‐Zentren‐Fragmentierung von 1‐Oxo‐5‐oximino‐9‐methyl‐ trans ‐decalin. Fragmentierungsreaktionen, 22. Mitteilung
Author(s) -
Grob C. A.,
von Tschammer H.
Publication year - 1968
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.19680510509
Subject(s) - chemistry , sodium ethoxide , decalin , medicinal chemistry , fragmentation (computing) , oxime , stereospecificity , sodium hydroxide , ethanol , stereochemistry , organic chemistry , catalysis , computer science , operating system
The reaction rates of heterolytic fragmentation of 5‐( p , ‐toluenesulfonyloxyimino)‐1‐oxo‐9‐methyl‐ trans ‐decalin ( 1 ), induced by sodium hydroxide in 80% ethanol and by sodium ethoxide in 100% ethanol, has been determined. The reaction of the oxime tosylate 1 with sodium ethoxide is first order with respect to both reactants. A similar base‐dependence is observed in the reaction of the oxime tosylate 1 with sodium hydroxide. These results are explained in terms of an addition‐fragmentation mechanism. This involves reversible addition of NaOH or NaOC 2 H 5 to the carbonyl group of the oxime tosylate 1 and concerted fragmentation of the addition compounds 5a and 5b , yielding 9‐cyano‐6‐methyl‐ trans ‐non‐5‐enoic acid ( 4a ) and the corresponding ethyl ester 4b , respectively. These reaction appear to be the first cases of concerted and stereospecific 7‐centre fragmentation.