Nickel-catalyzed asymmetric arylations of [alpha]-halocarbonyl compounds and studies of boratabenzene-containing transition metal complexes

Abstract

Chapter 1 begins with a review of the current literature on cross-coupling methods to generate a-arylcarbonyl compounds, with a special emphasis on asymmetric arylations. The second section of chapter 1 describes the development of an asymmetric Negishi arylation of a-bromoketones using a nickel/pybox catalyst. The third section details the development of a Suzuki arylation of a-bromo- and a-chloroamides using aryl-(9-BBN) reagents. Both of these cross-coupling procedures are stereoconvergent, as they convert the racemic starting electrophile to an enantioenriched product. Chapter 2 describes new studies into the chemistry of boratabenzene-containing transition-metal complexes. In particular, a new method for preparing complexes bearing a diphenylphosphidoboratabenzene ligand is disclosed, starting from a transition metal-diphenylphosphide and a boracycle, which is an intermediate in the synthetic route previously used in the preparation of these complexes. In addition, the preparation and characterization of a new, tri-ortho-substituted variant of potassium diphenylphosphidoboratabenzene is described. This new species is used as a ligand in an iron complex, which is characterized. In addition, preliminary studies towards the synthesis of palladium complex bearing this new ligand are disclosed.