Beilstein J. Org. Chem.2020,16, 1092–1099, doi:10.3762/bjoc.16.96
54, 10000 Zagreb, Croatia NMR Centre, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia 10.3762/bjoc.16.96 Abstract In order to prepare novel polycyclic derivatives of bicyclo[3.2.1]octadiene systems fused with a thiophene ring, photochemical cyclization and aldol condensation
reactions were carried out. The starting substrates were easily obtained by a Vilsmeier–Haack reaction of bicyclo[3.2.1]octadiene thiophene derivatives with dimethylformamide. From the obtained carbaldehydes, novel methyl, methoxy, and cyano-substituted styryl thienobenzobicyclo[3.2.1]octadiene derivatives
[3.2.1]octadiene compound with an extended conjugation.
Keywords: bicyclo[3.2.1]octadiene; photocyclization; thiophene; Vilsmeier–Haack reaction; Wittig reaction; Introduction
The bicyclo[3.2.1]octane skeleton has become the subject of intensive research in recent years [1][2][3]. Its presence in
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Graphical Abstract
Figure 1:
Known biologically active bicyclo[3.2.1]octenes/octadienes.
Beilstein J. Org. Chem.2014,10, 2222–2229, doi:10.3762/bjoc.10.230
the incorporation of deuterium in the bicyclo[3.2.1]octadiene moiety and a methoxy group on the N=C oxazoline bond by 1,4-addition or more likely by addition to the N=C bond followed by keto–enol tautomerization giving 14. The adducts are spectroscopically completely identified (see Supporting
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Graphical Abstract
Scheme 1:
Synthesis of 4- (1) and 5-(2-vinylstyryl)oxazoles (2).