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Electrophilic Additions to Strained Bridgehead Olefins. Estimation of Strain by Comparison with the Solvolysis of Bridgehead Bromides
Author(s) -
Becker Konrad B.
Publication year - 1977
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.19770600112
Subject(s) - chemistry , solvolysis , nonane , bicyclic molecule , electrophilic addition , bromide , acetic acid , medicinal chemistry , bridged compounds , electrophile , hydrogen bromide , double bond , ring strain , hammett equation , reaction rate constant , organic chemistry , hydrolysis , bromine , molecule , catalysis , physics , quantum mechanics , kinetics
The addition of water, acetic acid, and hydrogen bromide to the strained bridge‐head olefins bicyclo[3.3.1]‐1(2)‐nonene (1) , bicyclo[4.2.1]‐1(8)‐nonene (2) , and bicyclo[4.2.1]‐1(2)‐nonene (3) gives exclusively the bridgehead alcohols, acetates, and bromides, respectively. The reaction rate constants for the addition of acetic acid to the bridgehead olefins 1,2 and 3 , and the solvolysis rates for the related 1‐bromo‐bicyclo[3.3.1]nonane (4) and 1‐bromobicyclo[4.2.1]nonane (5) were measured. A comparison of the activation enthalpies of these two reactions gives an estimate of relative strain of the bridgehead double bond. The strain in the bicyclo[4.2.1]nonenes 2 and 3 is similar to that in trans ‐cyclooctene (8‐9 kcal/mol).