Nucleophilic addition to a p-benzyne derived from an enediyne: a new mechanism for halide incorporation into biomolecules.
Biosynthesis of haloaromatics ordinarily occurs by electrophilic attack of an activated halogen species on an electron-rich aromatic ring. We now present the discovery of a new reaction whereby a nucleophilic halide anion can be attached even to an aromatic ring without activating substituents. We show that the enediyne cyclodeca-1,5-diyn-3-ene, in the presence of lithium halide and a weak acid, is converted to 1-halotetrahydronaphthalene. The kinetics are consistent with rate-limiting cyclization to a p-benzyne biradical that rapidly adds halide and is then protonated. This reaction has interesting mechanistic features and important implications for incorporation of halide into biomolecules.
Perrin
Charles L
CL
Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093-0358, USA. cperrin@ucsd.edu
Rodgers
Betsy L
BL
O'Connor
Joseph M
JM
D000838:Anions / Q000737:chemistry; D001555:Benzene Derivatives / Q000737:chemistry*; D053281:Enediynes / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D015394:Molecular Structure
D000838:Anions; D001555:Benzene Derivatives; D053281:Enediynes; D006219:Halogens