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Studies on the 1,3‐Dipolar Cycloaddition of 3‐Arylsydnone Nitrile Oxides to Cyclic Alkene Compounds
Author(s) -
Smh MeiHsiu,
Her KueiHua,
Yeh MouYung
Publication year - 2001
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200100169
Subject(s) - nitrile , cycloaddition , chemistry , alkene , cyclohexene , homo/lumo , 1,3 dipolar cycloaddition , medicinal chemistry , ring (chemistry) , photochemistry , organic chemistry , catalysis , molecule
Cycloadditions of 3‐arylsydnone nitrile oxides ( 1 ) with various cyclic alkenes led to 4‐isoxazolyl or 4‐isoxazolinyl sydnones. The reactions were controlled either by the HOMO (dipole)‐LUMO (dipolarophile) interaction or by the LUMO (di pole)‐HOMO (dipolarophile) interaction. The former were accelerated by electron withdrawing substituted dipolarophiles, such as 2‐cycloalken‐1‐ones ( 3a∼3c ), etc., while the latter were improved by the dipolarophiles with electron‐donating substituents, such as 1‐morpholino‐1‐cyclohexene ( 3d ), 1,3‐cyclohexadiene ( 3e ). Be sides that, methylenecycloalkanes 3f∼3g are more active than cyclohexene to ward cycloaddition with nitrile ox ides 1 . The cycloaddition ad ducts may serve as useful building blocks in synthesis through chemical modification and ring cleavage, and also be employed in the syntheses of many natural products with significant and special activities.