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Ring inversion in the isomerization of syn- to anti-6-alkylbicyclo[3.1.0]Cihexanesemidiones

✍ Scribed by Glen A. Russell; John J. McDonnell

Publisher: Elsevier Science
Year: 1968
Tongue: French
Weight: 183 KB
Volume: 9
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(00)75411-6

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✦ Synopsis

We have previously postulated (1,2) the rearrangement of a-6ethylbicyclo[3.l.O]hexanesemidione to the anti isomer.

We have now found that the w-6-methyl semidione is much more stable and that isomerization to the anti isomer can be followed by esr spectroscopy. The rearrangement with R = methyl proceeds to completion in dimethyl sulfoxide in the presence of potassium A-butoxide in 3 hrs, whereas the rearrangement of the w-ethyl compound occurs in 1 min under similar conditions.

The steric driving force is emphasized by the observation that the G-6-deuterium compound does not show the rearrangement.

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