Steric effects in bicyclic ring systems. II. Angle strain and non-bonding repulsion in base-catalyzed deuterium exchange of bicyclic ketones

✍ Scribed by Satya P. Jindal; Sangeeta S. Sohoni; Thomas T. Tidwell

• Publisher: Elsevier Science
• Year: 1971
• Tongue: French
• Weight: 196 KB
• Volume: 12
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)96555-4

✦ Synopsis

It has been found that rates of base-catalyzed deuterium exchange of bicyclic ketones2'3'4 and bicyclic nitriles are a sensitive probe for the chemical consequenc-e~ of structural variation. Results reported herein for exchange of bicyclo[Z.l..l]hexan-Z-one (2) and bicyclo[Z.Z.Z]octan-Z-one (c). when compared to the corresponding rates for bicyclo[Z.Z.l]heptan-Z-one (i), establish that angle strain (I-strain) and non-bonded van der Waals repulsion (F-strain) are major contributors to the rate differences. Results on methyl-substituted bicycloheptyl derivatives reported in Part III6 indicate that torsional strain7 has an indeterminate influence. Hybridization effects' are not detected in these reactions but may still be operative. The rates of exchange are