Regioselective heck reaction of aliphatic olefins
Date of Issue2014
School of Physical and Mathematical Sciences
The thesis presents selective Heck reaction of terminal aliphatic olefins. Previously, the reaction used to give a complex mixture of isomers. The first part is about Heck reaction of aliphatic olefins using aryl triflates. A new ferrocene bisphosphine dnpf was developed to give high internal regioselectivity. The ligand dnpf is now commercialized by Sigma-Aldrich. Our experimental and DFT studies indicated that the bulky dnpf ligand disfavored terminal insertion via steric effect. The second part is about selective Heck reaction of alphatic olefins using aryl bromides and chlorides. The method can also be applied to styrenes. The selectivity was again controlled by dnpf. Methanol solvent and acidic additive n-Bu3NHCl were needed to to promote halide dissociation from neutral aryl palladium complexes via hydrogen bonding. DFT calculation of halide dissociation indicated that hydrogen bonding by methanol and ammonium salt with bromide affected halide dissociation both thermodynamically and kinetically.