Beta elimination path

Although the Sn of leaving groups bound to a sp center is a mechanism that has been searched for, with one or two rare exceptions there is little evidence in the literature that it has ever been found. The correct mechanism is path AdN, addition to a polarized multiple bond, followed by path Ep, beta elimination from an anion. 

Path Ep, Beta Elimination from an Anion or Lone Pair... 

A stabilized anion forms first via path p.t., and then a fair leaving group departs in the slow step via the beta elimination from an anion path Ep. (See Section 4.3 for more... 

This is the almost exclusive route in basic media for replacement of a leaving group hound to a donble bond. This reaction was introduced in Section 4.5, Nucleophilic Substitution at a Trigonal Planar Center. The most common substrates for this reaction are the carboxyl derivatives. A nucleophile adds first via path Adileaving group departs via the beta elimination from an anion path Ep. 

Two elimination paths are possible beta elimination from an anion (path Ep),... 

The reaction of ODC6 DO to form a five member ring ODY(C5 )CDO radical has the lowest barrier of only 15 kcal mol This ODY(C5 )CDO radical can beta scission (eliminate) a formyl radical with a 37 kcal mof barrier to form cyclopentadiene-one (ODY(C5)). It is important to note that resonantly stabilized radicals of cyclopentadiene and cyclopentadiene-ones are formed in the oxidation steps of aromatic systems. Their thermochemistry, reaction paths and kinetics all need to be analyzed for the inclusion of aromatics in combustion mechanisms. 

The pentadiene formyl radical C4C DO (Path-2) reacts further by beta scission to form CO and butadienyl-1 (CDCCDC ) via a barrier of 39 kcal mof. The butadienyl-1 can undergo elimination, which has a 40 kcal mof barrier, to form vinyl radical and acetylene or react with molecular oxygen with no barrier. 

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