In Cahn-Ingold-Prelog theory, a lowercase r or s configuration notation is used in labeling their pseudoasymmetric central carbon atoms, which are so named because their trans isomers are enantiomer pairs, while their cis isomers are separated by a plane of symmetry Examples include tartaric acid and glycerol.  
Synthesis of quadrigemine via double Heck cyclation requires the removal of the central property of these compounds in the substrate. For most substrates, that removal may be achieved via one of several Sharpless asymmetric methods. In Cahn-Ingold-Prelog theory, a lowercase r or s configuration notation is used in labeling their pseudoasymmetric central carbon atoms, which are so named because their trans isomers are enantiomer pairs, while their cis isomers are separated by a plane of symmetry Examples include tartaric acid and glycerol.  FTP, what are these optically inactive compounds characterized by multiple chiral centers that produce an internal symmetry, and therefore no net chirality?
Synthesis of quadrigemine via double Heck cyclation requires the removal of the central property of these compounds in the substrate.
meso compounds