Stephen Daniel Pastor

Novel sterically congested chiral tripodal phosphite ligands: catalytic asymmetric hydrosilylation of ketones with a Rh(I)–TRISPHOS catalyst

Abstract A new chiral trisphosphite ligand, ( S,S,S )-2,2′,2″-tris(2,4,8,10-tetra- tert -butyl-dibenzo[ d,f ][1,3,2]dioxaphosphepin-6-yl-6-oxy)tri-2-propylamine, ( S,S,S )-TRISPHOS, was synthesized and coordination chemistry investigated. The Rh(I)–( S,S,S )-TRISPHOS complexes were found to be effective catalysts for the enantioselective hydrosilylation of ketones.

Sterically Congested Bisphosphite Ligands for the Rhodium(I)-Catalyzed Hydrosilation of Ketones

Sterically congested bisphosphites were shown to be effective ligands for the Rh-catalyzed hydrosilation of ketones with diphenylsilane. The hydrosilation of 4-alkylcyclohexanones and ( m )-menthone led to a significant proportion of the less stable (axial) alcohol, which suggests that these reactions are under kinetic, rather than thermodynamic, control.

Facile Phosphite to Phosphonate Rearrangement of a Trialkanolamine-derived Triphosphite Promoted by Triethylaluminum 1

A facile room temperature rearrangement of a trialkanolamine-derived triphosphite, 1 , to the monophosphonate 5 promoted by three equivalents of triethylaluminum is described. The diphosphonate 6 was prepared by the addition of three equivalents of triethylaluminum to the monophosphonate 5 . A mechanism is suggested involving a transition state or intermediate with coordination of the trialkylaluminum to the migrating oxygen.