An improved method for the bromination of metalated haloarenes via lithium, zinc transmetalation: a convenient synthesis of 1,2-dibromoarenes.
A facile protocol for the synthesis of 1,2-dibromoarenes is described. A standard ortho-lithiation/bromination procedure, when applied to bromoarenes, resulted in poor yields of the corresponding 1,2-dibromoarenes (13-62% yield). However, transmetalation of the transient aryllithium intermediate to an arylzinc species with ZnCl2, followed by bromination, resulted in dramatically improved yields of the synthetically useful 1,2-dibromoarenes (68-95% yield).
Merck Research Laboratories, Department of Process Research, Merck & Co., Inc., 466 Devon Park Drive, Wayne, Pennsylvania 19087, USA. karsten_menzel@merck.com
Karsten
K
Menzel
Ethan L
EL
Fisher
Lisa
L
Dimichele
Doug E
DE
Frantz
Todd D
TD
Nelson
Michael H
MH
Kress
D001966:Bromine / Q000737:chemistry*; D001969:Bromobenzenes / Q000138:chemical synthesis*; D008094:Lithium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D001969:Bromobenzenes; D008094:Lithium; D015032:Zinc; D001966:Bromine