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The Thermal Isomerizations of Bicyclo[2.1.0]pent‐5‐yl Methyl Ketones: endo‐exo stereomutation and cyclopropyl‐allylic rearrangement to cyclopent‐2‐enyl methyl ketones
Author(s) -
Grosclaude JeanPierre,
Gonzenbach HansUlrich,
Perlberger JeanClaude,
Schaffner Kurt
Publication year - 1976
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.19760590830
Subject(s) - chemistry , isomerization , allylic rearrangement , bicyclic molecule , ketone , cleavage (geology) , medicinal chemistry , stereochemistry , photochemistry , organic chemistry , catalysis , geotechnical engineering , fracture (geology) , engineering
Bicyclo[2.1.0]pent‐5‐yl methyl ketones undergo two thermal isomerization reactions. The endo‐exo stereomutation follows the ring‐flip path in better than 90%, with inversion of the configuration of the angular carbon atoms by cleavage and reclosure of the central bond. Stereomutation and cyclopropyl‐allylic rearrangement to cyclopent‐2‐enyl methyl ketone do not involve a common intermediate and proceed on separate potential energy surfaces. The activation parameters of the rearrangement suggest an allowed concerted cycloreversion process.