The Di-π-methane Photorearrangement of 2,3-Disubstituted Benzobarrelenes and Benzonorbornadiene − Substituent Effects in Regioselectivity

5.06 Di-π-methane, Oxa-di-π-methane, and Aza-di-π-methane Photoisomerization

“…Additional information on the reaction mechanism was obtained from the transformation of similar benzobarrylene derivatives under the same conditions. 49 Aromatic heterocyclic compounds have also efficiently been transformed. Thus, the polycyclic benzopyrazino derivative 74 was obtained from the reaction of the corresponding benzobarrylene substrate 75 (Scheme 15).…”

(1RS,2RS,3SR,4SR,9RS)-1,2,3,9-Tetrabromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene

“…Some of these flame retardant products contain brominated organic compounds (Burleigh et al, 1980). Besides industrial applications for these highly brominated compounds, such as pesticides, plastics, fire-retardants and pharmaceutical chemicals, they also play an important role as key compounds for the synthesis of other derivatives (Altundaş et al, 2002;Altundaş & Balcı, 1993). In this connection, great interest has been focused on the halogenation of benzonorbornadiene (Daştan et al, 1994(Daştan et al, , 2002Altundaş et al, 2000;Cristol & Nachtigall, 1967).…”

Unveiling the Unexpected Reactivity of Electrophilic Diazoalkanes in [3+2] Cycloaddition Reactions within Molecular Electron Density Theory

“…Recently, NBD has also found applications in molecular photoswitches to absorb solar radiation [5], and by 2018, more than 30 thousand publications and patents had reported their production and applications in various fields [1]. The behavior of NBD derivatives in the Wagner-Meerwein rearrangement [6,7], photochemical di-π methane rearrangement [8], Diels Alder reactions [9], catalytic reactions with alkynes [10] and several other instances [1] have established their uniqueness as organic reagents and fostered their wide synthetic applications in [3+2] cycloaddition (32CA) reactions to form isoxazolidines, triazoles, carbocycles and other heterocycles of biological and environmental relevance [11][12][13][14][15]. In 2001, Tam and coworkers [16,17] reported the highly regio-and stereoselective intramolecular 32CA reactions of NBD-tethered nitrones and nitrile oxides (Scheme 1).…”