Cycloaddition Reactions of 1,4‐Dihydronaphthalene‐1,4‐epoxide with Cyclohexadiene and 7‐(Methoxycarbonyl)cycloheptatriene: Selectivity in Additions

Abstract

Cycloaddition reactions of naphthalene‐1,4‐epoxide (1) with both 7‐(methoxycarbonyl)cycloheptatriene (2) and cyclohexadiene (4) give adducts of type 3 and 5 exclusively. Selectivity was observed for the cycloaddition and bromination reactions, but neighboring group participation also occurrs in the latter. The formation of the products is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Cycloaddition Reactions of Benzonorbornadiene and Homonorbornadiene: New Isoxazoline and Pyridazine Derivatives

“…). Cycloadditions to the double bond of the compounds such as norbornadiene derivatives were occurred form exo faces because of electron density . The electron density of isolated double bond belongs to benzonorbornadiene ( 4 ), and data (NMR and HRMS) of adducts 7a – d are consistent with the proposed structures.…”

“…It may be said that the γ‐Gauche effect in 17 is higher than that of 16 . Because the chemical shifts of H c in 16 (2.74 ppm) are smaller than that of 17 (3.37 ppm) . We explained that resonance at higher field (173.2 ppm) of CO groups in the cis ‐compound 15 than that (174.3 ppm) of the trans ‐compound 14 is caused by steric repulsion .…”

“…We reported γ‐Gauche effects in some products 14 – 17 including cyclopropane rings (Fig. ) . γ‐Gauche effect in the cyclopropane rings of 14 and 15 is higher in the cis ‐compound 15 than that of trans ‐compound 14 .…”

“…Norbornadiene derivatives including nitrogen–oxygen atoms and their rearrangement products may be important. Cycloaddition reactions of some strained compounds such as norbornadiene and norbornadiene derivatives with nitrile oxides and tetrazines were reported . To the best of our knowledge, cycloaddition reactions of homonorbornadienes ( 5 ) with nitrile oxides and tetrazine have not been investigated.…”

Synthesis and some enzyme inhibition effects of isoxazoline and pyrazoline derivatives including benzonorbornene unit

“…Pyramidalized alkenes such as benzonorbornadiene react with reagents such as bromine and diene from exo face because the electron density is higher in this face. [3,[14][15][16][17][18][19][20][21][22][23][24] If the exo approach of the reagents to alkenes is hindered due to the steric effect, products formed by the endo approach can be obtained. [64,65] In addition, the exo-syn approach of the reagents to these alkenes is unfavorable due to the steric effect.…”