Ynone Co-Coordination at a Nickel Borane Complex: An Assessment of Secondary Coordination Sphere Effects.

Secondary coordination sphere ligand effects can be used to direct or organize small molecule substrates at a metal center. Herein, we assess the bifunctional ambiphilic diphosphine, tri-tert-butylboranyldiphosphinoethane (ttbbpe) and its ability to influence stereoselective substrate coordination, while appended to nickel. This report takes a synthetic/computational approach to test the impacts and limitations associated with ligand-directed substrate coordination using [Ni(ttbbpe)(η2:η2-COD)] (COD = 1,5-cyclooctadiene) and ynones (alkynes having an α-carbonyl group at the propargylic position) as model substrates.