Synthesis and molecular structure of chiral metallo-based sterically overcrowded alkenes

A four step synthesis of pyridyl-2-yl-thioxanthen-9-ylidene-isoquinolines is described. The corresponding palladium complexes are the first examples of a novel class of chiral, metallo-based, sterically overcrowded alkenes. The crystal and molecular structure of the palladium dichloride complex shows an anti-folded helical configuration with significant distortion of the central olefinic bond.