Details

Autor(en) / Beteiligte

• Riggs, Jason C
• Ramirez, Antonio
• Cremeens, Matthew E
• Bashore, Crystal G
• Candler, John
• Wirtz, Michael C
• Coe, Jotham W
• Collum, David B

Titel

Structural and Rate Studies of the Formation of Substituted Benzynes

Ist Teil von

• Journal of the American Chemical Society, 2008-03, Vol.130 (11), p.3406-3412

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2008

Quelle

MEDLINE

Beschreibungen/Notizen

• The key elimination step for the formation of 3-substituted and 3,6-disubstituted benzynes from 2-haloaryllithiums displays a pronounced solvent-dependent regioselectivity. All 2-haloaryllithiums with electron withdrawing groups in the 6 position are shown by 6Li and 13C NMR spectroscopic studies to be monomers in THF. DFT computational studies implicate trisolvates. Rate studies reveal that LiF eliminates via monomer-based pathways requiring THF dissociation whereas LiCl eliminates via nondissociative pathways. Elimination to form 3-chloro- and 3-fluorobenzyne from 2-chloro-6-fluorophenyllithium displays a pronounced solvent-dependent regioselectivity that is traced to competing solvent-dissociative and nondissociative dissociative pathways for the elimination of LiCl and LiF, respectively.