The abnormal claisen rearrangement II. High temperature chemistry of 1-ethyl-2-methylspiro[2,5]octa-4, 6-dien-8-one

✍ Scribed by Elliot N. Marvell; Bruce Schatz

• Publisher: Elsevier Science
• Year: 1967
• Tongue: French
• Weight: 205 KB
• Volume: 8
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)90948-1

✦ Synopsis

A considerable body of evidence supports the intermediacy of a 1,2-dialkylspiro[2,5]octadienone in the so-called abnormal Claisen rearrangement (1). Formation and reaction of this intermediate is formally analogous to the cis-1-alkyl-2-vinylcyclopropane valence isomerization (2), recently named the homodienyl-1,5 hydrogen shift (3). However, experimental evidence which would connect these two processes has been lacking.

We would like to report evidence which not only permits this connection, but also provides information about the stereochemistry of the transition state.