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Conformer Equilibria in 2,4‐Disubstituted Pentane Derivatives
Author(s) -
Hoffmann Reinhard W.,
Stenkamp Dirk,
Trieselmann Thomas,
Göttlich Richard
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199911)1999:11<2915::aid-ejoc2915>3.0.co;2-r
Subject(s) - conformational isomerism , chemistry , steric effects , substituent , pentane , computational chemistry , molecule , polar , stereochemistry , organic chemistry , physics , astronomy
2,4‐Disubstituted pentanes are molecules which adopt essentially only two conformations. Substituents have been varied in order to find those which lead to a strong preference of the conformer equilibrium. Studying 2‐substituted 4‐methylpentanes 3 and 4‐benzyloxypentanes 12 , it has been shown that substituent effects on the conformer equilibria are not additive, as would be expected on the grounds of steric effects alone. Rather, interactions between polar groups reinforce the bias of the conformer equilibria. When applied to 2,4‐disubstituted pentanes, substituents such as chloro or phthalimido shift the conformer equilibrium to the side of the gg conformer with preferences exceeding 90%.