Polar Addition of Hydrogen Halides onto Olefins

✍ Scribed by Prof. Dr. J. S. Dewar; Dr. R. C. Fahey

• Book ID: 102724654
• Publisher: John Wiley and Sons
• Year: 1964
• Tongue: English
• Weight: 562 KB
• Volume: 3
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.196402451

✦ Synopsis

Various ~truciures have been proposed for the interniediates of cktrophilic additions onfo olefrns; these inclirrle halonium ions, classical carboiium ions, r;-complexes (i. e. rionclassical carbonium ions), and Ti;-comple.ws with back-coordination. I t is shown here that it is impossible to use any one of these entities alone to explain all such electrophilic additions, the electrophilc itself determines the nature oj the transition state formed. Polar addition oj hydrogen halides onto olefins appears to proceed via a classical carboniun? ion which does not occw as the free ion but as an imdissociated ion pair. Varioiis other mechanisms ha) e been cxclirded by stirdies repried here OJ the stereochemical course o/ such additions.

Recent physical evidence [7] indicates that analogous metal complexes, e.g. Zeise's salt, are in fact double-bonded x- [ 6 ] M .