Palladium-mediated C-S, C-N, and C-O bond formation: Reductive elimination and catalytic reactions

New catalytic reactions for the formation of carbon-sulfur, carbon-nitrogen, and carbon-oxygen bonds were developed and their mechanisms for bond formation were studied. Mechanistic studies were performed with palladium thiolato complexes in order to study the carbon-sulfur bond-forming reductive elimination reaction. Reductive elimination to form the carbon-nitrogen bonds in N-aryl azoles and N-aryl imines from palladium azolyl and methyleneamido complexes was investigated, which led to a method for the palladium-catalyzed formation of N-aryl azoles and N-aryl imines. Palladium alkoxides as potential intermediates in palladium amination reactions were explored, which resulted in the first direct C-O bond-forming reductive elimination of ether from a palladium alkoxide complex. A method for the nickel and palladium-catalyzed formation of t-butyl aryl, methyl aryl and t-butyidimethyl silyl aryl ethers from aryl halides and sodium alkoxides or sodium siloxides was developed. Further catalyst modification extended palladium-catalyzed etherations to the formation of diaryl ethers. Aryl palladium phenoxide complexes were synthesized and their mechanism for C-O bond-forming reductive elimination of diaryl ethers was investigated. Reductive elimination to form diaryl ethers occurred from monomeric arylphosphines complexes and dimeric alkylphosphine complexes.