Synthesis of 2,3,6,7-tetrabromoanthracene

• Christian Schäfer,
• Friederike Herrmann and
• Jochen Mattay

Beilstein J. Org. Chem. 2008, 4, No. 41, doi:10.3762/bjoc.4.41

• . Keywords: anthracene; arenes; cyclizations; polycycles; ring closure; 2,3,6,7-tetrabromoanthracene; Introduction Anthracene and its derivatives are long known polycyclic aromatic compounds showing a high potential for use in materials science (e.g. fluorescence probing, photochromic systems

• , electroluminescence) and several reviews have been published so far [1][2][3]. Anthracenes may be readily functionalized in positions 9 and 10 due to their exceptional reactivity. The outer rings, however, can not be functionalized easily. There are some anthracene compounds available with one or two substituents at

• -cyclohexadiene as hydrogen donor. In this case, the structure and the purity of 4 were proven by NMR and high resolution mass spectrometry. The UV/VIS-spectra of 2,3,6,7-tetrabromoanthracene and anthracene in cyclohexane are shown in Figure 1. At first glance, both spectra resemble each other; however, all

The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate

• Shlomo Levinger,
• Ranjeet Nair and
• Alfred Hassner

Beilstein J. Org. Chem. 2008, 4, No. 32, doi:10.3762/bjoc.4.32

• ]. 9-Acetylanthracene does not lend itself to the Borch reductive amination, which entails a nucleophilic addition step of ammonia (or amine) to the carbonyl function [7]. Conjugation between the anthracene nucleus and an acyl substituent at position 9 is sterically inhibited by the flanking hydrogen

• for orthogonality between the planar function and the aromatic nucleus in the nitrogen derivatives of 9-acylanthracenes has been corroborated spectroscopically (lack of conjugation in the semicarbazide and the oxime). Furthermore, steric hindrance to attack at the cyano group of anthracene-9

• anthracene) is also worth noting in this context. Restricted rotation in acylnaphthalenes has been extensively studied [11]. Amino-substituted allyl sulfones 1 were deprotonated with LDA at −78 °C in THF and the lithio derivative obtained was allowed to react for a specified time at that temperature with