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1,3‐Dipolar cycloaddition reactions. Regioselective synthesis of heterocycles and theoretical studies
Author(s) -
Pierini Adriana B.,
Cardozo Mario G.,
Montiel Aida A.,
Albonico Sem M.,
Pizzorno Maria T.
Publication year - 1989
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570260420
Subject(s) - regioselectivity , chemistry , cycloaddition , 1,3 dipolar cycloaddition , molecular orbital , computational chemistry , derivative (finance) , medicinal chemistry , organic chemistry , molecule , catalysis , financial economics , economics
We report a 1,3‐dipolar cycloaddition reaction between a oxazolium 5‐oxide derivative with chloroacrylonitrile or ethyl propiolate as dipolarophiles, in order to obtain substituted pyrrolizidines. Experimentally we found that the reaction is regiospecific with chloroacrylonitrile and regioselective with ethyl propiolate. The secondary attractive orbital interactions from the Frontier Molecular Orbital Theory, the differences in stability of the possible biradical intermediaries postulated for the reaction and some hindrance effects, explain the regioselectivity observed experimentally.