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Intermolecular Reactions of γ ‐Halocarbanions – Stepwise Analogs of 1,3‐Dipolar Cycloaddition
Author(s) -
Barbasiewicz Michał,
Mąkosza Mieczysław
Publication year - 2012
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.201200428
Subject(s) - chemistry , intramolecular force , cycloaddition , intermolecular force , cyclopentanes , adduct , lewis acids and bases , deprotonation , computational chemistry , selectivity , medicinal chemistry , catalysis , stereochemistry , organic chemistry , molecule , ion
γ ‐Halocarbanions, short‐lived intermediates, add to electron‐deficient double bonds of aldehydes, Michael acceptors, and imines to form anionic adducts that enter intramolecular 1,5‐substitution to form five‐membered rings of tetrahydrofurans, cyclopentanes, and pyrrolidines, respectively. Although the γ ‐halocarbanions can be generated by simple deprotonation of appropriate precursors, a wealth of other methods based on Lewis acid‐catalyzed opening of cyclopropanes with formation of dipolar species utilizes a similar mechanistic scheme. In our review, we analyze kinetic relations of elementary processes in the multistep transformations, and demonstrate how structural factors influence the mechanisms and selectivity of the reaction.