title: Synthesis of Sterically Hindered Polychlorinated Biphenyl Derivatives.
abstract: A series of sterically hindered (methoxylated) polychlorinated biphenyl derivatives was synthesized using the Suzuki and the Ullmann coupling reaction. The Suzuki coupling with Pd(dba)(2)/2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (DPDB) gave better yields (65-98%) compared to the classic Ullmann coupling reaction (20-38%). Despite the reactive catalyst system, no significant coupling with aromatic chlorine substituents was observed. Crystal structure analysis of four PCB derivatives revealed solid state dihedral angles ranging from 69.7° to 81.0°, which indicates that these highly ortho substituted PCB derivatives have some conformational flexibility.
authors.affiliation: Department of Occupational and Environmental Health, The University of Iowa, College of Public Health, University of Iowa Research Campus, 221 IREH, Iowa City, IA 52242, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Joshi
authors.forename: S M
authors.initials: SM
authors.lastname: Vyas
authors.forename: M W
authors.initials: MW
authors.lastname: Duffel
authors.forename: S
authors.initials: S
authors.lastname: Parkin
authors.forename: H-J
authors.initials: HJ
authors.lastname: Lehmler