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Acid‐catalyzed hydrolysis of bridged bi‐ and tricyclic compounds. XXXIX—Kinetics and mechanisms of the hydration reactions of 1‐ and 3‐acetylnortricyclanes
Author(s) -
Lajunen Martti,
Salmi Jani,
Limnell Taru
Publication year - 2002
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.521
Subject(s) - chemistry , cyclopropane , protonation , perchloric acid , kinetic isotope effect , catalysis , deuterium , solvent , hydrolysis , kinetics , medicinal chemistry , acid catalysis , aqueous solution , ring (chemistry) , solvolysis , organic chemistry , ion , physics , quantum mechanics
The disappearance of 1‐ and 3‐acetylnortricyclanes ( 1‐Ac and 2‐Ac ) in aqueous perchloric acid was followed by capillary gas chromatography at different temperatures and acid concentrations. 1‐Ac is much less reactive than 2‐Ac . The activation parameters, solvent deuterium isotope effects and parameters of excess acidity equations were measured and the products studied. 1‐Acetylnortricyclane is hydrated according to the A ‐2 mechanism, i.e. the carbonyl oxygen is protonated in the fast pre‐equilibrium and one water molecule attacks at the rate‐limiting stage the partially open cyclopropane ring, producing 6‐acetyl‐2‐norborneols. 3‐Acetylnortricyclane is hydrated according to the Ad E 2 mechanism, i.e. the cyclopropane ring is slowly protonated and opened, with subsequent fast attack of water producing 3‐, 5‐ and 7‐acetyl‐2‐norborneols. Copyright © 2002 John Wiley & Sons, Ltd.