Evaluation of (sigma)-Donating Ability of a 9-Phosphatriptycene and Its Application to Catalytic Reactions

The low (sigma)-donating ability of 9-phosphatriptycene 1 was revealed by cyclic voltammetry and theoretical calculations. The tungsten complex of 1 was synthesized and the IR and NMR spectroscopic data of the complex also suggested the low (sigma)-donating ability of 1. 1 was shown to be effective as a ligand in the palladium-catalyzed reactions, the Stille coupling and the Heck reaction.