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Synthesis and Stereochemistry of Diepoxynaphthacenes and Tetraepoxyheptacenes
Author(s) -
Meier Herbert,
Rose Bernd
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970407
Subject(s) - cycloaddition , chemistry , dimethyl acetylenedicarboxylate , yield (engineering) , adduct , acetylenedicarboxylate , stereochemistry , medicinal chemistry , organic chemistry , catalysis , physics , thermodynamics
Cycloaddition reactions of 1,4‐dihydro‐1,4‐epoxynaphthalenes ( 2 ) and benzo[ c ]furans ( 4 ), generated in situ from the tetracyclone adducts of 2 , yield the diepoxynaphthacenes 5 (Schemes 1, 2). Out of 4 possible stereoisomers an exo‐exo and an exo‐endo geometry (A and C in Scheme 3) can be realized. The ratio A:C varies from pure A to pure C depending on the substituents of 2 and 4 . Stereoisomeric heptacenes 7 can be obtained by a twofold cycloaddition of the same type (Scheme 4). Only one π bond of reactive alkynes such as cyclooctyne or acetylenedicarboxylate is capable of an addition to 4 (Schemes 5, 6).