Synthesis 2011(7): 1045-1054  
DOI: 10.1055/s-0030-1258454
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of Sterically Hindered Polychlorinated Biphenyl Derivatives

S. N. Joshia, S. M. Vyasa, M. W. Duffelb, S. Parkinc, H.-J. Lehmler*a
a 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
Fax: +1(319)3354290; e-Mail: hans-joachim-lehmler@uiowa.edu;
b Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa, Iowa City, IA 52242, USA
c Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA
Further Information

Publication History

Received 10 November 2010
Publication Date:
01 March 2011 (online)

Abstract

A series of sterically hindered (methoxylated) polychlorinated biphenyl derivatives were synthesized using the Suzuki and the Ullmann coupling reactions. 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.

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Crystallographic data (excluding structure factors) for the structures in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication nos. CCDC 797054-797058. Copies of the data can be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44(1223)336033 or e-mail: deposit@ccdc.cam.ac.uk.