Low and high temperature bromination of exocyclic dienes: high temperature bromination. Part 16

2003-05-19
Horasan, N
Kara, Y
Azizoglu, A
Balcı, Metin
The electrophilic addition of bromine to an exocyclic diene, 5,6-dimethylenebicyclo[2.2.1]hept-2-ene, in CCl4 at 0degreesC led to the formation of non-rearranged (73%) and rearranged products (27%). However, high temperature bromination of the exocyclic diene at 77degreesC suppressed the formation of the rearranged products. Similarly, bromination of 9,10-dimethylenetricyclo[6.2.1.0(2.7)]undeca-2,4,6-triene at -10degreesC gave only the exo-1,2-addition product. Bromination at +5degreesC resulted in the formation of a mixture consisting of exo-1,2- and 1,4-addition products in a ratio of (1:4). High temperature bromination at 77degreesC resulted in the formation of the endo-1,2-addition product. Furthermore, it has been shown that the 1,4-addition product converts smoothly to the 1,2-addition product. The formation mechanism of the products is discussed and supported by calculations.

Suggestions

High temperature bromination. Part 18: Bromination of benzonorbornadiene derivatives: Polybrominated benzonorbornenes and benzonorbornadienes
Dastan, A; Balcı, Metin (Elsevier BV, 2005-06-06)
The low and high temperature bromination reactions of bromobenzonorbornadiene derivatives were studied and the possible role of a neighboring group in rearrangements was investigated. New polybrominated benzonorbornadiene and benzonorbornene derivatives were synthesized. All compounds were characterized property Using NMR spectroscopy.
Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst
Okumus, Seda; Tanyeli, Cihangir; Demir, Ayhan Sıtkı (Elsevier BV, 2014-07-30)
The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of alpha-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti).
Distyryl-boradiazaindacenes: facile synthesis of novel near IR emitting fluorophores
Dost, Zeynep; Atilgan, Serdar; Akkaya, Engin U. (Elsevier BV, 2006-09-04)
Boradiazaindacenes with methyl substituents at 3 and 5 positions were for the first time shown to undergo efficient double condensation reactions with an aromatic aldehyde yielding a series of extended conjugation dyes. These new fluorophores have absorption maxima in the range of 650-660 nm. The dyes reported here have large quantum yields with 20 nm Stokes' shifted emission peaks. The straightforward synthesis of such red shifted BODIPY derivatives is important in relation to the synthesis of novel and us...
Manganese(III) acetate based tandem oxidation of various cyclic β-alkoxy α,β-unsaturated ketones
Tanyeli, Cihangir (Elsevier BV, 2000-10-07)
We describe the unusual preliminary results of manganese(III) acetate based tandem oxidation of various β-alkoxy 2-cyclopentenone and 2-cyclohexenone derivatives to afford corresponding α′-acetoxy-α′-phenyl substituted oxidation products in good yields.
Synthesis of various camphor-based chiral pyridine derivatives
Tanyeli, Cihangir; Isik, M (Elsevier BV, 2004-07-19)
(+)-beta-Hydroxymethylenecamphor 1 and enamines 2a-e were transformed into chiral camphor-based pyridine derivatives 3a-e via a tandem condensation reaction in good yields.
Citation Formats
N. Horasan, Y. Kara, A. Azizoglu, and M. Balcı, “Low and high temperature bromination of exocyclic dienes: high temperature bromination. Part 16,” TETRAHEDRON, pp. 3691–3699, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57812.