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Fluorine as a Regiocontrol Element in the Ring Opening of Bicyclic Aziridiniums
Author(s) -
Lam Yuhong,
Houk Kendall N.,
Cossy Janine,
Gomez Pardo Domingo,
Cochi Anne
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.201200461
Subject(s) - chemistry , regioselectivity , bicyclic molecule , piperidine , ring (chemistry) , pyrrolidine , nucleophile , stereochemistry , azide , nucleophilic substitution , medicinal chemistry , organic chemistry , catalysis
The origin of the variation in the regioselectivity of the nucleophilic ring opening of a series of bicyclic aziridinium ions derived from N ‐alkylprolinols was investigated by quantum‐chemical computations (M06‐2X/6‐31+G(d,p)‐SMD). These aziridiniums differ only in the degree and the configurations of F‐substitution at C(4). With the azide ion as nucleophile, the ratio of the piperidine to the pyrrolidine product was computed. An electrostatic gauche effect influences the conformation of the adjoining five‐membered ring in the fluorinated bicyclic aziridinium. This controls the regioselectivity of the aziridinium ring opening.