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The S N 2 Transition State. 6: Breakdown of the Reactivity–Selectivity Principle in the S N 2 Reaction of α‐Halocarbonyl Compounds. A Molecular Orbital Analysis [1]
Author(s) -
Kost Daniel,
Aviram Kalman
Publication year - 1985
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198500118
Subject(s) - chemistry , sn2 reaction , nucleophile , reactivity (psychology) , selectivity , molecular orbital , reaction coordinate , alkyl , computational chemistry , nucleophilic substitution , transition state , photochemistry , medicinal chemistry , organic chemistry , molecule , catalysis , medicine , alternative medicine , pathology
A molecular orbital (MO) analysis of the S N 2 transition state (TS) of α‐carbonyl derivatives is described with various nucleophile leaving group pairs. On the basis of this analysis it is shown that the enhanced selectivity toward nucleophiles observed in α‐halocarbonyl compounds is directly associated with S N 2 rate enhancement. Both observations result from a stabilizing frontier orbital interaction between a high lying π‐type three center orbital along the reaction coordinate axis and the carbonyl π‐system. The magnitude of interaction is greater for more powerful nucleophiles, resulting in both greater reactivity as well as additional selectivity relative to simple alkyl halides.