Characteristics of polychlorinated biphenyl (PCB) atropisomers

Abstract

We have prepared and characterized the atropisomers of 3 PCBs, namely 2,2′,3,4,6-penta-[I],2,2′,3,4,4′,6-hexa-[II] and 2,2′,3,3′,4,4′,6,6′-octachlorobiphenyls [III]. On the basis of the rotational stability of these 3 enantiomer pairs, we can predict that, of the 78 PCBs which possess axial chirality, the enantiomers of at least 19 PCBs containing 3 or 4 ortho chlorines would be stable to racemization at room temperature.