Principally, the double bond in any chiral molecule is dissymmetrically deformed even if this unsaturated center is situated far from its chiral center. However, discus-
sions in this article are limited solely to the synthesis and stereochemistry of the com-
pounds whose double-bond systems 1 playa decisive role in the generation of their
chirality by being explicitly twisted in the molecular environment (e.g. ring) surround-
ing the unsaturated cehter.