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Die Solvolyse von α‐Bromstyrolen Substitution am ungesättigten trigonalen Kohlenstoffatom
Author(s) -
Grob C. A.,
Cseh G.
Publication year - 1964
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.19640470126
Subject(s) - chemistry , solvolysis , carbonium ion , medicinal chemistry , acetophenone , amine gas treating , heterolysis , electrophilic substitution , electrophile , ethanol , catalysis , stereochemistry , organic chemistry , hydrolysis
In ‘80%’ ethanol the or‐bromostyrenes 5a ‐ 5d undergo unimolecular solvolysis to the corresponding acetophenones. In addition to acetophenone, α‐bromostyrene itself yields a minor amount of phenylacetylene. The p ‐amino, p ‐methoxy and p‐ acetamido derivatives 5b‐5c react 10 8 , 10 4 and 10 3 times as fast, respectively, as the unsubstituted compound 5a , the rates being insensitive to 1‐5 equivalents of triethyl‐ amine. Furthermore, 5a and 5c show electrophilic catalysis by silver ion. A two‐step ionisation mechanism involving a digonal carbonium ion ( p ‐R‐C 6 H 4 C=CH 2 ) + is thus indicated.